Science & Electronics Calculators

Calculate voltage, current, or resistance from the other two electrical quantities.

Estimate voltage drop from current, resistance, and optional starting voltage.

Calculate electrical power from voltage and current, with an optional power factor.

Calculate force from mass and acceleration.

Calculate pressure from force and area.

Calculate kinetic energy from mass and speed.

Calculate mechanical work from force and displacement.

Calculate mechanical power from work and time.

Estimate runtime from battery energy capacity, device power draw, and an efficiency allowance.

Calculate wave speed from frequency and wavelength for basic physics and classroom problems.

Calculate molar concentration from the amount of solute in moles and total solution volume in litres.

Calculate the driven-to-driver gear ratio and ideal output speed from tooth counts and input RPM.

Calculate torque magnitude from a perpendicular force and lever arm distance.

Convert a repeating signal frequency to its period, or a period to frequency, using reciprocal relationships.

Estimate the unloaded output voltage of a two-resistor voltage divider.

Calculate average water flow in litres per second and litres per minute from volume and elapsed time.

Estimate average flow velocity in a circular pipe from a volumetric flow rate and internal diameter.

Estimate ideal-gas pressure from amount of gas, absolute temperature and container volume using SI units.

Calculate heat energy for a mass, specific heat capacity and temperature change under a simple constant-capacity assumption.

Calculate ideal spring force magnitude from a spring constant and displacement using Hooke’s law.

Calculate equivalent resistance for two or three resistors connected in parallel.

Calculate wavelength and period from wave speed and frequency when both use consistent SI units.

Compare useful output power with input power and calculate conversion efficiency and losses.

Compare output force with input force to estimate ideal mechanical advantage.

Calculate signed linear momentum from mass and velocity in SI units.

Estimate gravitational potential energy relative to a chosen height using mass and gravitational acceleration.

Calculate impulse from average net force acting over a specified time interval.

Estimate final concentration and solvent volume using solute conservation in a dilution.

Add two to four ideal resistances connected in series.

Calculate charge transferred by a constant current over an elapsed time.

Estimate ideal projectile flight time, horizontal range and maximum height from launch speed, angle and gravity.

Calculate the inward force and acceleration needed for circular motion from mass, speed and radius.

Estimate buoyant force from fluid density and displaced volume, then compare it with an object’s weight.

Calculate gauge and absolute pressure at depth in a static fluid using density, gravity and surface pressure.

Estimate length change and final length from thermal expansion coefficient, original length and temperature change.

Convert a positive power ratio to decibels and view the equivalent amplitude ratio under compatible impedance assumptions.

Estimate ideal transformer secondary voltage from primary and secondary winding turns and primary voltage.

Calculate equivalent capacitance for two or more ideal capacitors connected in series and in parallel.

Calculate the RC time constant, approximate five-time-constant interval and first-order cutoff frequency.

Estimate conductor resistance from material resistivity, length and cross-sectional area with unit conversion.

Calculate Reynolds number from fluid density, speed, characteristic diameter and dynamic viscosity.

Estimate the mutual gravitational attraction between two masses separated by a center-to-center distance.

Calculate elastic potential energy and signed restoring force for an ideal linear spring.

Estimate electrostatic force between two point charges and determine whether their signs imply attraction or repulsion.

Estimate sensible heat absorbed or released from mass, specific heat capacity and temperature change.

Estimate preliminary generator wattage from running load, largest motor start-up demand and a reserve allowance.

Estimate LED series resistance and power dissipation from supply voltage, forward voltage and target current.

Calculate ideal capacitive reactance from AC frequency and capacitance.

Calculate ideal inductive reactance from frequency and inductance.

Estimate the ideal LC resonant frequency and period from inductance and capacitance.

Estimate apparent power, active input power and output power for a balanced three-phase system.

Calculate signal-to-noise power ratio and its decibel value from comparable signal and noise powers.

Combine two or three independent sound levels logarithmically instead of adding decibel values directly.

Estimate hydraulic pump output and input power from flow rate, head, fluid density and overall efficiency.

Calculate amount of gas in moles from pressure, volume and absolute temperature using PV=nRT.

Calculate approximate molar mass from a simple chemical formula using a documented element table.

Calculate linear magnification from image height and object height.

Combine positive thermal resistance values in series and calculate the reciprocal overall U-value.

Estimate sound level change with distance under an ideal free-field inverse-square approximation.

Convert a flow rate in litres per minute into litres per second and cubic metres per hour.

Estimate hydrostatic gauge pressure from fluid density, vertical head and gravitational acceleration.

Estimate the upward buoyant force from the density and volume of displaced fluid.

Estimate the length change of a material from original length, expansion coefficient and temperature change.

Estimate the period and frequency of an ideal simple pendulum for a stated length and gravity.

Calculate focal length and optical power from positive object and real-image distances using the thin-lens relation.

Calculate equivalent resistance for a list of positive resistors connected in series or in parallel.

Estimate battery charging time from capacity added, average charging current and an entered overall efficiency.

Estimate solar electricity production over a period from installed capacity, peak-sun-hours and a performance ratio.

Calculate centripetal acceleration and force for a body moving along a circular path at a stated speed.

Estimate kinetic friction force from mass, coefficient of friction and gravitational acceleration on a level surface.

Estimate terminal speed under a simplified quadratic-drag model from mass, density, area and drag coefficient.

Calculate final solution volume and diluent volume using C1V1 = C2V2 for compatible concentration units.

Calculate rest energy from mass using Einstein’s E = mc² relation and convert joules to kilowatt-hours.

Calculate average compressive stress from an axial force and loaded cross-sectional area.

Calculate thermal diffusivity from conductivity, density and specific heat capacity for a uniform material.

Calculate heat-pump coefficient of performance from useful thermal energy delivered and electricity consumed in the same period.

Calculate power factor and an idealized reactive-power estimate from real power and apparent power.

Calculate solar self-consumption and self-sufficiency rates from generation, on-site solar use and total site load.

Estimate line current in a balanced three-phase system from power, line-to-line voltage, power factor and overall efficiency.

Estimate transformer efficiency and losses from measured input and output power over the same operating interval.

Estimate a theoretical maximum module count per string from open-circuit voltage corrected for a chosen minimum temperature and an inverter voltage limit.

Estimate dry-air density from absolute pressure and air temperature using the ideal-gas approximation.

Compare average electrical load with peak demand to calculate load factor for a defined measurement period.

Calculate the ideal stored energy of a capacitor from capacitance and voltage using the standard electrostatic energy relationship.

Estimate near and far focus limits from focal length, aperture, subject distance and an assumed circle of confusion.

Estimate charging energy loss and wall-to-battery efficiency from electricity drawn and energy added to the battery.

Estimate solar charging time from battery capacity, current state of charge, average available PV power and system efficiency.

Calculate median, p95 and p99 latency estimates from a list of measured request durations in milliseconds.

Calculate uptime percentage and total downtime over a defined reporting window from measured hours.

Calculate cache hit and miss percentages from observed requests to quantify how often requests are served from cache.

Estimate average in-flight requests from request throughput and average response latency using Little’s Law.

Estimate daily and monthly transfer volume from request count and average payload size.

Estimate origin-transfer volume and a simple transfer-cost scenario from monthly data and cache-hit percentage.

Estimate average monthly data transfer per active user from total site transfer and active-user count.

Estimate row data, index overhead and a growth scenario for a database table or dataset.

Estimate retained log storage from event rate, average event size, retention days and replication factor.

Estimate required ventilation airflow from room volume and target air changes per hour, with a CFM conversion.

Estimate straight-pipe friction loss using the Darcy–Weisbach equation from flow, diameter, length and friction factor.

Estimate usable energy between starting and reserve state of charge for a battery of known capacity and discharge efficiency.

Estimate annual solar energy and value lost under a user-supplied shading-loss percentage.

Estimate extra webhook retry volume and data transfer from event volume, failure rate, retry count and payload size.

Calculate average elapsed time from code-ready events to production releases using measured total duration and deployment count.

Calculate the share of deployments that needed rollback, hotfix or incident remediation under your documented definition.

Estimate mean operating time between observed failures using total operating time and a measured failure count.

Calculate mean repair duration from total repair hours and completed repair events.

Estimate steady-state availability from mean time between failures and mean time to repair.

Calculate allowable downtime during a reporting window from an availability target percentage.

Compare observed failed-request percentage with an allowed failure budget and estimate how quickly the budget is being consumed.

Calculate the fraction of API requests that meet your defined error criterion in a measured period.

Calculate aggregate CPU busy time as a percentage of available CPU time across a host or fleet.

Calculate used memory as a share of total available memory using consistent units such as GiB.

Estimate queue utilization from arrival and service rates using a simplified stable single-server model.

Measure active database connections against the configured pool limit.

Estimate transfer time for a backup dataset using effective throughput and a stated protocol/processing allowance.

Estimate retained backup storage from full copies, daily incremental data and retention days.

Estimate months until storage reaches capacity at a constant net monthly growth rate.

Estimate the share of link capacity consumed by a measured average or peak throughput.

Estimate dew-point temperature from air temperature and relative humidity using a common Magnus approximation.

Estimate water vapour mass per air volume from temperature and relative humidity using a saturation vapour pressure approximation.

Calculate mean fluid velocity from volumetric flow and internal pipe diameter, using a circular cross-section.

Estimate panel output adjustment from rated power, cell temperature and a stated temperature coefficient.

Estimate future annual solar output and cumulative energy using a constant annual degradation assumption.

Compare a battery’s current draw or charge current with its rated amp-hour capacity.

Estimate charging efficiency and charging losses from wall energy and energy added to the vehicle battery.

Calculate heat transferred from mass, specific heat capacity and temperature change.

Estimate a material’s specific heat capacity from supplied heat energy, mass and temperature change.

Calculate the angular magnification of a simple telescope from objective and eyepiece focal lengths.

Estimate the exit-pupil diameter from telescope aperture and magnification.

Convert a lens’s actual focal length into a 35 mm equivalent using the camera crop factor.

Estimate a room’s RT60 reverberation time using the Sabine equation and total equivalent absorption.

Calculate sensitivity, specificity, positive predictive value, negative predictive value and accuracy from a confusion matrix.

Estimate how many devices fit within a Power over Ethernet switch’s power budget after reserving a margin.

Calculate focal length and magnification from positive object and image distances for a thin-lens geometry.

Calculate spring force and stored elastic energy from a spring constant and displacement within the linear range.

Estimate Young’s modulus from tensile force, original length, cross-sectional area and measured extension in a linear-elastic specimen.

Estimate reactive power compensation needed to move from a measured lagging power factor to a higher target factor.

Calculate the running share of a compressor’s observed run/rest cycle.

Estimate the final temperature when two quantities of water at different temperatures are mixed without heat loss.

Estimate conductive heat transfer through a flat layer from conductivity, area, temperature difference, thickness and duration.

Estimate downstream fluid velocity from pressure, inlet velocity, elevation difference and density under ideal Bernoulli assumptions.

Calculate angular momentum and rotational kinetic energy from moment of inertia and angular speed for rotation about a fixed axis.

Estimate impulse and velocity change from a constant net force acting over a duration on a stated mass.

Calculate the central-axis moment of inertia for a uniform solid cylinder and uniform solid sphere from mass and radius.

Estimate ideal extension force from hydraulic pressure and piston bore diameter, using pressure and area units explicitly.

Estimate compressed-air receiver recovery time from tank volume, pressure rise and compressor free-air delivery.

Estimate heat-exchanger effectiveness as actual heat transfer divided by a supplied maximum theoretical heat transfer.

Estimate ideal and efficiency-adjusted mechanical advantage from supporting rope segments and a supplied efficiency.

Calculate how many samples mono or multichannel digital audio contains for a recorded duration.

Estimate a simplified indoor CO₂ excess concentration from generation and fresh-air flow.

Calculate uniform angular acceleration from the change in angular velocity over time.

Estimate the time sound takes to travel a distance using an assumed sound speed.

Calculate classical kinetic energy from momentum and mass without converting velocity first.

Estimate fluid mass flow rate from volumetric flow and density using consistent SI units.

Estimate rolling resistance for level motion from mass, coefficient of rolling resistance and gravitational acceleration.

Calculate stored rotational kinetic energy from moment of inertia and angular speed in revolutions per minute.

Estimate mechanical shaft power from transmitted torque and rotating speed.

Estimate mean fluid speed in a round pipe from volumetric flow rate and its internal diameter.

Calculate theoretical linear belt speed from pulley diameter and revolutions per minute.

Calculate ideal-gas molecular root-mean-square speed from absolute temperature and molar mass.

Estimate pressure drag from fluid density, speed, frontal area and an assumed drag coefficient.

Calculate elastic energy stored in an ideal linear spring from stiffness and extension.

Estimate gravitational acceleration at a spherical body’s surface from its mass and radius.

Calculate a propagating sound wave’s wavelength from wave speed and frequency.

Resistor Power from Voltage Calculator estimates W using voltage across resistor (v), resistance (ohms). Applies to ideal resistive loads; actual component wattage and cooling need safety margins.

Capacitor Electric Charge Calculator estimates coulombs using capacitance (µf), applied voltage (v). Capacitor ratings, tolerances and stored energy matter in real circuits.

Two Parallel Resistors Calculator estimates ohms using first resistance (ohms), second resistance (ohms). Assumes exactly two ideal resistors connected in parallel.

DC Wire Voltage Drop Calculator estimates V using one-way cable length (m), dc current (a), conductor resistance (ohms/m). Temperature and actual conductor resistance must be verified; not a cable-sizing safety approval.

Sound Level Distance Change Calculator estimates dB decrease using reference distance (m), new distance (m). Reflections, directional sources and air absorption can make measurements differ.

Hydraulic Fluid Power Calculator estimates W using pressure difference (kpa), volumetric flow (l/s). Actual shaft or pump power is higher because of mechanical and hydraulic losses.

Humidity Vapor Pressure Deficit Calculator estimates kPa using air temperature (°c), relative humidity (%). The saturation pressure approximation is intended for normal environmental temperatures.

Mechanical Impulse Calculator estimates N·s using average force (n), force duration (s). This assumes force average is representative; it also equals momentum change.

Blackbody Thermal Radiation Flux Calculator estimates W/m² using absolute temperature (k), surface emissivity. This is emitted surface power, not net exchange with another surface.

Thermal Resistance Heat Flow Calculator estimates W using temperature difference (k), thermal resistance (k/w). Applies to a steady-state lumped thermal resistance, not transient building performance.

Escape Velocity Calculator uses central body mass kg and distance from center m to calculate m/s. Newtonian estimate; no atmosphere, rotation or relativistic correction.

Circular Orbit Period Calculator uses central body mass kg and orbital radius from center m to calculate seconds. Ideal circular Newtonian orbit around a single massive body.

Moving Observer Doppler Frequency Calculator uses source frequency hz and sound speed m/s to calculate Hz. Assumes a stationary source and motion along the sound path.

Light Travel Time Calculator uses travel distance km to calculate seconds. Vacuum speed; media and gravitational effects are excluded.

Blackbody Peak Wavelength Calculator uses absolute temperature kelvin to calculate nm. Uses Wien displacement law for an ideal blackbody.

Sound Power Intensity Calculator uses acoustic source power w and distance m to calculate W/m². Free-field spherical spreading with no absorption or reflections.

Magnetic Flux Through Area Calculator uses magnetic field t and area m² to calculate Wb. Assumes a uniform static magnetic field and planar area.

Parallel Plate Electric Field Calculator uses voltage difference v and plate separation m to calculate V/m. Ideal uniform field; edge fringing and material effects excluded.

Series RL Impedance Calculator uses resistance ω and inductance h to calculate ohms. Magnitude only; does not show phase angle or coil parasitics.

Engineering Strain Calculator uses original length mm and final length mm to calculate %. Engineering strain differs from true strain at large deformations.

DC Cable Resistive Loss Calculator uses current a and total round-trip cable resistance ω to calculate W. Does not include contact losses, AC skin effect or thermal limits.

Power Bank Deliverable Energy Calculator uses cell bank rating mah and nominal cell voltage v to calculate Wh. Marketing mAh ratings usually describe internal cells, not USB output capacity.

Power Supply Headroom Calculator uses rated output w and expected continuous load w to calculate %. Headroom below zero indicates overload; transient peaks need additional allowance.

Parallel Solar Strings Current Calculator uses parallel strings and operating current per string a to calculate A. Combine only electrically compatible strings and apply code-compliant protection.

Parallel Battery Bank Energy Calculator uses number of batteries and nominal battery voltage v to calculate Wh. Nominal energy is not usable energy; chemistry and depth of discharge matter.

Inverter Delivered Power Calculator uses dc input power w and inverter efficiency percent to calculate W. Real inverter efficiency varies by load and temperature.

PWM Average Voltage Calculator uses supply voltage v and pwm duty cycle percent to calculate V. Averaged voltage assumes ideal switching and adequate filtering.

Sine RMS from Peak Voltage Calculator uses sine peak voltage v to calculate V RMS. Only valid for an undistorted sinusoidal waveform.

Parallel Branch Current Divider Calculator uses total current a and branch one resistance ω to calculate A branch 1. Only two ideal resistors in parallel; branch one current is shown.

Battery Usable Depth of Discharge Calculator uses nominal battery energy wh and allowed depth of discharge percent to calculate Wh. Battery controls and temperature can further reduce usable energy.

Two-Mass Centre of Mass Position uses first mass kg and first position m to calculate metres. Works on one coordinate axis for point masses, excluding external constraints.

Impulse from Constant Force uses net force magnitude n and force duration seconds to calculate N s. For a variable force use the time integral rather than a constant-force estimate.

Linear Momentum Magnitude uses moving mass kg and speed m per second to calculate kg m/s. Momentum is directional; this returns only the magnitude.

Angular Wavenumber from Wavelength uses wavelength metres to calculate rad/m. For periodic waves in a uniform medium, not attenuation or dispersion.

Oscillation Period from Angular Frequency uses angular frequency rad per second to calculate seconds. Assumes harmonic periodic motion with fixed angular frequency.

Photon Energy from Wavelength uses vacuum wavelength nm to calculate eV. Approximate physical constant in electron-volts nanometers, vacuum wavelength.

Ideal Gas Molar Density uses absolute pressure pa and absolute temperature kelvin to calculate mol/m³. Ideal gas assumption fails at certain extreme pressures and temperatures.

Total Internal Reflection Critical Angle uses higher refractive index and lower refractive index to calculate degrees. Requires incident light traveling from higher to lower refractive index.

Hydraulic Force from Pressure uses applied pressure pa and piston effective area m² to calculate N. Ignores friction, pressure losses and dynamic piston forces.

Sound Propagation Delay uses source distance metres and sound speed metres per second to calculate ms. Sound speed varies with medium temperature and humidity.

Water Filter Tank Turnover uses water system volume l and effective filtration flow litres/hour to calculate hours. One theoretical circulation does not guarantee complete water treatment.

Daily Water per Person uses household water used litres and meter period days to calculate L/person/day. Leakages, guests and seasonal changes affect measured usage.

Waste Collection Bin Requirement uses expected waste volume l and effective bin capacity litres to calculate bins. Requires room for segregation and limits imposed by collection service.

Solar Array Snow Energy Loss uses expected snow-free period generation kwh and estimated snow-related loss percent to calculate kWh. Snow cover and climate are highly variable; use monitored data if available.

Water Tower Hydrostatic Pressure uses water height m and water density kg/m³ to calculate kPa. Static pressure only; friction and pump effects change delivered pressure.

Food Waste Mass Diverted uses food waste generated kg and composted share percent to calculate kg. Assumes diverted material reaches a suitable composting process.

Pool Evaporation Water Loss uses exposed water surface m² and estimated evaporation mm per day to calculate L/day. Evaporation depends on humidity, wind, cover and temperature.

Rain Garden Infiltration Duration uses ponded depth mm and infiltration rate mm per hour to calculate hours. Assumes constant infiltration and no incoming rainfall during drainage.

Renewable Energy Share uses renewable source electricity kwh and total electricity kwh to calculate %. Use matched boundary, period and source attribution for the accounting.

Operational CO2 Emissions Intensity uses total operational emissions kg co2e and energy consumed kwh to calculate kg/kWh. Intensity depends on scope and emission factor methodology, not universal estimates.

Battery Energy at State of Charge uses battery rated capacity wh and state of charge percent to calculate Wh. Nominal available capacity changes with temperature, age and load.

Appliance Idle Energy per Month uses idle power w and idle hours per day to calculate kWh. Actual devices may alternate between sleep states.

Electric Heater Energy Usage uses rated heater power kw and effective full-power operation hours to calculate kWh. Thermostat cycling means full-power equivalent hours differ from clock time.

USB Charger Output Power uses measured usb output volts and usb output current amps to calculate W. USB power delivery modes and negotiated current vary.

Electric Fan Daily Energy uses average fan running watts and daily fan runtime hours to calculate kWh. Speed changes and standby draw add to measured consumption.

Solar Panel Series String Voltage uses panels in series and module operating voltage v to calculate V. Cold-weather open-circuit voltage and electrical code limits must be checked separately.

Battery Discharge Current uses device power demand w and supply voltage v to calculate A. Battery current changes as voltage, efficiency and load vary.

LED Strip Power Supply Capacity uses installed led strip length m and rated w per metre to calculate W. Select a certified supply with safe thermal margin and proper wiring.

Standby Usage Hours from Energy uses measured standby kwh and standby power w to calculate hours. Assumes fixed standby power and excludes active usage.

Single Phase Apparent Power uses rms supply voltage v and rms current amps to calculate VA. Apparent power is not real watts unless power factor is one.

Distance Under Constant Acceleration uses initial velocity m/s and elapsed time seconds to calculate m. Displacement can be negative; assumes constant acceleration.

Force from Mass and Acceleration uses mass kg and acceleration m/s squared to calculate N. A negative sign expresses force direction along the chosen axis.

Sliding Friction Work Magnitude uses average friction force newtons and sliding distance metres to calculate J. Magnitude only; frictional work is negative relative to the direction of motion.

Spring Potential Energy uses spring constant n/m and spring compression metres to calculate J. Assumes a linear Hooke law spring within elastic range.

Capillary Rise Height Estimate uses liquid surface tension n/m and contact angle degrees to calculate m. Assumes a cylindrical narrow tube and ideal static contact angle.

Water Heating Thermal Energy uses water volume litres and temperature rise celsius to calculate kWh. Approximates one litre of water as one kilogram; excludes heater losses.

Linear Momentum uses mass kilograms and velocity m/s to calculate kg m/s. Momentum sign follows the velocity axis.

Ideal Lever Output Force uses applied input force n and input lever arm m to calculate N. Neglects friction, deformation and changing lever angles.

Liquid Density from Mass and Volume uses liquid sample mass kg and sample volume litres to calculate kg/m³. Temperature affects density; use measurements at a stated temperature.

Radiative Heat Flux Difference uses surface emissivity and hot surface kelvin to calculate W/m². Uses ideal Stefan Boltzmann emission between black-equivalent environments.

Calculate capacitor charge from capacitance from capacitance uf, volts. The result is expressed in mC. Real capacitors may exhibit leakage and voltage-dependent capacitance.

Calculate resistor series power loss from amps, ohms. The result is expressed in W. Assumes steady current and an appropriate resistor rating.

Calculate resistor parallel total current from volts, r1, r2. The result is expressed in A. Assumes ideal parallel resistors under the same voltage.

Calculate rc lowpass cutoff frequency from ohms, cap uf. The result is expressed in Hz. Ideal first-order RC network; component tolerances apply.

Calculate capacitor ac reactance from frequency hz, capacitance uf. The result is expressed in ohms. For ideal capacitance at a single sinusoidal frequency.

Calculate parallel capacitor total capacitance from cap1, cap2, cap3. The result is expressed in µF. Parasitic capacitance and voltage ratings are not modeled.

Calculate resistive divider output voltage from vin, r top, r bottom. The result is expressed in V. Assumes the output is unloaded.

Calculate ac inductor reactance from frequency hz, inductance mh. The result is expressed in ohms. For ideal inductance at a single sinusoidal frequency.

Calculate transformer ideal secondary voltage from primary volts, primary turns, secondary turns. The result is expressed in V. Ideal transformer ignores losses and saturation.

Calculate led series resistor value from supply volts, led volts, led count, amps. The result is expressed in ohms. Component ratings and wiring safety must be verified.

Calculate water pipe flow from cross section from diameter mm, velocity mps. The result is expressed in L/min. Assumes a full circular pipe with uniform mean velocity.

Calculate fluid dynamic pressure from density, speed. The result is expressed in Pa. Dynamic pressure is not the same as total pipe pressure.

Calculate water tank fill height rate from flow lpm, area m2. The result is expressed in cm/min. Assumes constant cross-sectional area and no outflow.

Calculate hydraulic piston displacement from bore mm, stroke mm. The result is expressed in L. Uses bore-side volume and ideal cylindrical geometry.

Calculate hydraulic annulus fluid volume from bore mm, rod mm, stroke mm. The result is expressed in L. Uses rod-side annular volume and full stroke.

Calculate open channel rectangular discharge from width, depth, velocity. The result is expressed in m³/s. Assumes uniform velocity; actual channels vary with depth.

Calculate tank emptying fixed flow from tank l, outflow lpm. The result is expressed in hours. Flow may change with pressure or water height.

Calculate rainfall intensity volume over area from area m2, rain mm. The result is expressed in L. Assumes 100% capture without runoff or evaporation losses.

Calculate fluid pressure to head water from pressure kpa. The result is expressed in m. Applies to water at approximate density 1000 kg/m³.

Calculate pump wire to water efficiency from hydraulic kw, input kw. The result is expressed in %. Motor, pump and drive losses are rolled into one estimate.

Calculate rotating wheel rim speed from diameter m, rpm. The result is expressed in m/s. Assumes no tire slip.

Calculate average impact force from stop time from mass kg, speed mps, stop seconds. The result is expressed in N. Assumes uniform deceleration and does not model force peaks.

Calculate inclined plane parallel weight from mass kg, angle deg. The result is expressed in N. Assumes a static object without friction.

Calculate ballistic horizontal range level ground from speed mps, angle deg. The result is expressed in m. Ignores aerodynamic drag and ground elevation differences.

Calculate circular motion revolution period from radius m, speed mps. The result is expressed in seconds. Assumes a constant tangential speed.

Calculate ideal damped oscillation frequency from natural hz, damping ratio. The result is expressed in Hz. Underdamped linear oscillator approximation only.

Calculate motor torque from shaft power from power kw, rpm. The result is expressed in N·m. Ideal mechanical shaft output without drivetrain losses.

Calculate flywheel energy from inertia from inertia, rpm. The result is expressed in J. The inertia must refer to the chosen axis.

Calculate pendulum frequency from length from length m. The result is expressed in Hz. Valid for small angular displacements.

Calculate work from constant force angle from force n, distance m, angle deg. The result is expressed in J. Only the component of force parallel to travel contributes work.

Calculate wind power available swept area from air density, diameter m, speed mps. The result is expressed in kW. This is wind power available, not a turbine's delivered electric power.

Calculate solar array peak coverage fraction from array kw, peak load kw. The result is expressed in %. Nameplate rating is not continuous output, and may exceed 100%.

Calculate battery round trip energy loss from charged, discharged. The result is expressed in kWh. Do not mix charging and discharging from different cycles.

Calculate heat pump output from cop from electricity kwh, cop. The result is expressed in kWh. COP varies with conditions and should be measured over a defined period.

Calculate heating degree hour estimate from setpoint c, mean outside c, hours. The result is expressed in degree-hours. Simplified temperature average, not a weather-normalized model.

Calculate refrigerator door open duty energy from open minutes, extra watts. The result is expressed in Wh. Added power is an assumed measurement, not a fixed appliance constant.

Calculate building envelope air leak volume from room m3, ach, hours. The result is expressed in m³. Air changes per hour must be measured or estimated carefully.

Calculate thermal mass temperature rise from energy kwh, mass kg, cp kj kg k. The result is expressed in °C. Assumes uniform heating and no heat losses.

Calculate electricity peak to average ratio from peak kw, energy kwh, hours. The result is expressed in ratio. Demand peaks and energy use must cover comparable intervals.

Calculate solar battery charge days from required kwh, solar daily kwh, efficiency percent. The result is expressed in days. Ignores changing weather, battery limits and standby losses.

Calculate kettle heating energy from Water litres, Temperature rise °C, Heating efficiency %. Get the result in kWh with a worked formula and clear assumptions: Ignores heat lost from the kettle body and ambient temperature.

Calculate led strip power draw from LED strip length metres, Rated W per metre. Get the result in watts with a worked formula and clear assumptions: Driver losses and dimming are excluded.

Calculate inverter standby energy from Standby watts, Hours in standby. Get the result in kWh with a worked formula and clear assumptions: The input is standby draw, not energy delivered to a load.

Calculate battery usable backup hours from Usable battery kWh, Average load kW. Get the result in hours with a worked formula and clear assumptions: Assumes constant load and already-adjusted usable capacity.

Calculate pump electricity consumption from Pump power W, Operating hours. Get the result in kWh with a worked formula and clear assumptions: Real pump power changes with duty cycle and flow.

Calculate heat pump compressor hours from Elapsed hours, Compressor duty %. Get the result in hours with a worked formula and clear assumptions: Defrost cycles and variable-speed operation can change the duty.

Calculate solar inverter power capping from Available DC kW, Inverter AC rating kW. Get the result in kW with a worked formula and clear assumptions: An inverter may provide a lower output because of temperature or grid restrictions.

Calculate vehicle accessory energy draw from Accessory W, Hours running. Get the result in kWh with a worked formula and clear assumptions: Does not include traction, charging or conversion losses.

Calculate thermal water storage capacity from Water litres, Temperature change °C. Get the result in kWh with a worked formula and clear assumptions: Assumes liquid water and neglects tank heat losses.

Calculate heating zone operating hours from Days, Daily heating hours. Get the result in hours with a worked formula and clear assumptions: This is scheduled time, not energy demand.

Calculate spring mass oscillation period from Mass kg, Spring stiffness N/m. Get the result in seconds with a worked formula and clear assumptions: Applies to an ideal small-amplitude spring–mass oscillator.

Calculate pendulum small angle period from Pendulum length m, Gravity m/s². Get the result in seconds with a worked formula and clear assumptions: Accurate only for sufficiently small swing angles.

Calculate mechanical work from force from Force N, Displacement m, Angle degrees. Get the result in joules with a worked formula and clear assumptions: Angle is between force vector and displacement vector.

Calculate linear momentum from Mass kg, Velocity m/s. Get the result in kg·m/s with a worked formula and clear assumptions: A signed velocity gives signed momentum along the chosen axis.

Calculate momentum change in a collision from Object mass kg, Initial signed velocity m/s, Final signed velocity m/s. Get the result in kg·m/s with a worked formula and clear assumptions: Velocity components must use the same signed axis; not a scalar impact force.

Calculate reynolds number from velocity from Density kg/m³, Speed m/s, Characteristic diameter m, Dynamic viscosity Pa·s. Get the result in dimensionless with a worked formula and clear assumptions: Flow regime interpretation depends on geometry and roughness.

Calculate angular frequency from hertz from Frequency Hz. Get the result in radians/second with a worked formula and clear assumptions: This is angular frequency, not rotations per minute.

Calculate force from uniform pressure from Uniform pressure pascals, Contact area m². Get the result in newtons with a worked formula and clear assumptions: Requires a uniformly distributed normal pressure and correctly measured contact area.

Calculate electric field strength from Force N, Test charge C. Get the result in N/C with a worked formula and clear assumptions: Works for magnitude when force and charge are positive.

Calculate capacitor stored energy from Capacitance farads, Voltage volts. Get the result in joules with a worked formula and clear assumptions: Use charged voltage; this is stored ideal energy.

Use the Sound Wavelength in Air to calculate m from Sound speed m per s, Frequency Hz. See the underlying formula, units, a worked example, and key limitation: Sound speed changes with air temperature and humidity.

Use the Echo Reflector Distance to calculate m from Echo delay seconds, Sound speed m per s. See the underlying formula, units, a worked example, and key limitation: Assumes the echo follows a single round-trip path.

Use the Sound Power Level Difference to calculate dB from Sound power A W, Sound power B W. See the underlying formula, units, a worked example, and key limitation: This compares power, not sound pressure at an arbitrary location.

Use the Octave Frequency Change to calculate Hz from Starting frequency Hz, Octave shift count. See the underlying formula, units, a worked example, and key limitation: Assumes the conventional doubling of frequency per octave.

Use the Sabine Reverberation Time to calculate seconds from Room volume m³, Equivalent absorption area m². See the underlying formula, units, a worked example, and key limitation: Sabine's approximation assumes a reasonably diffuse sound field.

Use the Speaker Alignment Delay to calculate milliseconds from Speaker path difference m, Sound speed m per s. See the underlying formula, units, a worked example, and key limitation: Distance difference is not necessarily the optimal delay in reflective rooms.

Use the Two Independent Sound Levels Combined to calculate dB from Sound level A dB, Sound level B dB. See the underlying formula, units, a worked example, and key limitation: Sources are assumed independent and measured on the same weighting scale.

Use the Audio Sampling Interval to calculate microseconds from Sampling rate Hz. See the underlying formula, units, a worked example, and key limitation: Sampling interval does not specify analog system latency.

Use the Relative Sound Exposure Energy to calculate relative units from Exposure duration hours, Relative sound intensity multiplier. See the underlying formula, units, a worked example, and key limitation: Relative energy is not a hearing safety assessment.

Use the Solar Array Area Power Density to calculate W per m² from Panel rated power W, Panel area m². See the underlying formula, units, a worked example, and key limitation: Rated lab power differs from real rooftop generation.

Use the Solution Mass Concentration from Molarity to calculate g/L from Concentration mol per liter, Molar mass g per mol. See the underlying formula, units, a worked example, and key limitation: Assumes the stated solute molar mass and homogeneous solution.

Use the Reactant Mole Ratio Yield to calculate mol from Moles of limiting reactant, Reactant stoichiometric coefficient, Product stoichiometric coefficient. See the underlying formula, units, a worked example, and key limitation: Assumes ideal complete conversion of limiting reactant.

Use the Substance Moles from Mass to calculate mol from Substance mass g, Molar mass g per mol. See the underlying formula, units, a worked example, and key limitation: Choose correct chemical formula and molar mass.

Use the Dilute Water ppm to mg/L to calculate mg/L from Approximate ppm by mass, Water density kg per liter. See the underlying formula, units, a worked example, and key limitation: Approximation assumes dilute aqueous solution and appropriate density.

Use the Hydroxide Concentration from pH to calculate mol/L from pH at 25 Celsius. See the underlying formula, units, a worked example, and key limitation: Assumes water at 25°C with pKw approximately 14.

Use the Ideal Gas Volume to calculate liters from Gas amount mol, Absolute temperature K, Pressure atm. See the underlying formula, units, a worked example, and key limitation: Approximate ideal-gas behavior; not suitable for nonideal conditions.

Use the Ideal Gas Density to calculate g/L from Molar mass g per mol, Pressure atm, Temperature K. See the underlying formula, units, a worked example, and key limitation: Assumes ideal behavior at the stated absolute temperature.

Use the Chemical Reaction Conversion Percentage to calculate % from Reactant consumed mol, Initial reactant mol. See the underlying formula, units, a worked example, and key limitation: Use consistent mole bases and distinguish conversion from selectivity.

Use the Solution Solute Mass Fraction to calculate % from Solute mass g, Total solution mass g. See the underlying formula, units, a worked example, and key limitation: The denominator includes solute plus solvent.

Use the Electrons from Electrolysis Charge to calculate mol electrons from Electrical charge coulombs. See the underlying formula, units, a worked example, and key limitation: Faraday constant is approximate; does not determine reaction products.

Use the Transformer Secondary Copper Voltage Drop to calculate V from Secondary current A, Secondary winding ohms. See the underlying formula, units, a worked example, and key limitation: Only winding resistive drop; leakage reactance is omitted.

Use the Transformer Loss from Efficiency to calculate W from Input power W, Measured efficiency percent. See the underlying formula, units, a worked example, and key limitation: Includes all losses only if efficiency measurement is accurate.

Use the AC Sine RMS Voltage to Peak to calculate V from Sinusoidal RMS voltage V. See the underlying formula, units, a worked example, and key limitation: Applies only to a sinusoidal waveform.

Use the AC Sine Peak Voltage to RMS to calculate V from Sinusoidal peak voltage V. See the underlying formula, units, a worked example, and key limitation: Applies only to a sinusoidal waveform.

Use the Resistor Joule Heat Dissipation to calculate W from Current A, Resistance ohms. See the underlying formula, units, a worked example, and key limitation: This is heat in a resistive load; account for thermal limits.

Use the LC Circuit Resonant Frequency to calculate Hz from Inductance henries, Capacitance farads. See the underlying formula, units, a worked example, and key limitation: Ideal LC circuit, excluding resistance and parasitic components.

Use the Two Series Capacitors Equivalent Capacitance to calculate microfarads from First capacitor µF, Second capacitor µF. See the underlying formula, units, a worked example, and key limitation: For two ideal capacitors in series.

Use the Inductive Reactance to calculate ohms from Frequency Hz, Inductance henries. See the underlying formula, units, a worked example, and key limitation: Applies to steady-state sinusoidal AC.

Use the Capacitive Reactance to calculate ohms from Frequency Hz, Capacitance farads. See the underlying formula, units, a worked example, and key limitation: Applies to steady-state sinusoidal AC.

Use the Three-Phase Apparent Power to calculate kVA from Line voltage V, Line current A. See the underlying formula, units, a worked example, and key limitation: Balanced three-phase system assumed.

Use the Shaft Torque from Power and RPM to calculate N m from Mechanical power W, Rotation speed rpm. See the underlying formula, units, a worked example, and key limitation: Assumes steady mechanical power at stated shaft speed.

Use the Wheel Angular Speed from RPM to calculate rad/s from Wheel revolutions per minute. See the underlying formula, units, a worked example, and key limitation: Does not include wheel slip.

Use the Centripetal Force from Speed to calculate N from Mass kg, Tangential speed m per s, Turn radius m. See the underlying formula, units, a worked example, and key limitation: For uniform circular motion only.

Use the Circular Track Lap Time to calculate seconds from Track radius m, Travel speed m per s. See the underlying formula, units, a worked example, and key limitation: Assumes a perfect circle and constant speed.

Use the Spring Potential Energy to calculate joules from Spring constant N per m, Spring compression or extension m. See the underlying formula, units, a worked example, and key limitation: Only for linear elastic spring deformation.

Use the Rectangular Beam Bending Stress to calculate Pa from Bending moment N m, Section width m, Section depth m. See the underlying formula, units, a worked example, and key limitation: Simple elastic bending formula; not a structural safety certification.

Use the Mechanical Motor Efficiency to calculate % from Mechanical output W, Electrical input W. See the underlying formula, units, a worked example, and key limitation: Measure both powers under the same operating conditions.

Use the Gear Teeth Output Speed Ratio to calculate rpm from Input shaft rpm, Driving gear teeth, Driven gear teeth. See the underlying formula, units, a worked example, and key limitation: Ideal gear pair; no slippage or losses.

Use the Solid Disk Moment of Inertia to calculate kg m² from Disk mass kg, Disk radius m. See the underlying formula, units, a worked example, and key limitation: Assumes a uniform solid disk about its center axis.

Use the Pulley Belt Linear Speed to calculate m/s from Pulley speed rpm, Pulley diameter m. See the underlying formula, units, a worked example, and key limitation: Assumes belt motion without slip.

Calculate % for coefficient of variation using Standard deviation, Mean value. Includes the formula, input validation, an example with real numbers, and practical limitations. Not meaningful when the mean is near zero; use a consistent data scale.

Calculate z for z-score from observation using Observed value, Reference mean, Population standard deviation. Includes the formula, input validation, an example with real numbers, and practical limitations. The reference distribution must be interpreted appropriately.

Calculate mean for combined mean of two groups using Group A mean, Group A sample size, Group B mean, Group B sample size. Includes the formula, input validation, an example with real numbers, and practical limitations. Assumes means refer to comparable quantities.

Calculate score for weighted score from two assessments using First score, Second score, First score weight %. Includes the formula, input validation, an example with real numbers, and practical limitations. The two scores must be on the same scale.

Calculate percentage points for proportion margin of error using Estimated percentage, Sample size, Critical z value. Includes the formula, input validation, an example with real numbers, and practical limitations. Simple random sampling approximation; weighting changes precision.

Calculate percentage points for proportion standard error using Estimated percentage, Sample size. Includes the formula, input validation, an example with real numbers, and practical limitations. Approximation is less reliable for very small samples or extreme probabilities.

Calculate % for both independent events probability using Event A probability %, Event B probability %. Includes the formula, input validation, an example with real numbers, and practical limitations. Only valid if events A and B are independent.

Calculate % for either independent event probability using Event A probability %, Event B probability %. Includes the formula, input validation, an example with real numbers, and practical limitations. The union formula assumes independence.

Calculate dB for signal-to-noise power ratio db using Signal power W, Noise power W. Includes the formula, input validation, an example with real numbers, and practical limitations. Power measurements must use the same units and bandwidth basis.

Calculate units for measurement repeatability range using Maximum measured value, Minimum measured value. Includes the formula, input validation, an example with real numbers, and practical limitations. Range alone does not describe uncertainty or systematic bias.

Calculate W for dc circuit electrical power using Circuit voltage V, Current A. Includes the formula, input validation, an example with real numbers, and practical limitations. Actual dissipation and wiring limits require engineering checks.

Calculate Wh for battery energy from amp hours using Nominal voltage V, Battery capacity Ah. Includes the formula, input validation, an example with real numbers, and practical limitations. Usable energy is lower depending on discharge limit and temperature.

Calculate kWh/day for solar array daily energy estimate using Array rating kW, Equivalent full-sun hours, System performance ratio %. Includes the formula, input validation, an example with real numbers, and practical limitations. Clouds, shading and local irradiance strongly affect yield.

Calculate kWh for meter reading energy used using Beginning reading kWh, Ending reading kWh. Includes the formula, input validation, an example with real numbers, and practical limitations. Energy use cannot be negative for cumulative readings without reset.

Calculate W for usb power budget using Powered ports, Rated watts per port. Includes the formula, input validation, an example with real numbers, and practical limitations. Shared-power chargers may cap total output below summed ratings.

Calculate A for parallel solar string current using Parallel strings, Short-circuit current per string A. Includes the formula, input validation, an example with real numbers, and practical limitations. Use protective equipment sized for design current and applicable electrical code.

Calculate Wh for power bank usable usb energy using Battery nameplate energy Wh, Conversion efficiency %. Includes the formula, input validation, an example with real numbers, and practical limitations. Rated conditions and battery health change available energy.

Calculate W/channel for led controller power per channel using Total LED strip power W, Controller output channels. Includes the formula, input validation, an example with real numbers, and practical limitations. Actual channel loading must be checked individually and wiring must be rated accordingly.

Calculate kWh for electric motor energy consumption using Motor draw kW, Running hours. Includes the formula, input validation, an example with real numbers, and practical limitations. Average draw may differ from motor nameplate rating.

Calculate V for resistive voltage divider output using Input voltage V, Top resistance Ω, Bottom resistance Ω. Includes the formula, input validation, an example with real numbers, and practical limitations. Assumes negligible output loading and a simple two-resistor divider.