Buoyant Force Calculator
Archimedes’ principle estimates the upward buoyant force exerted by a fluid on a displaced volume. Comparing buoyancy with the object’s weight offers a simple force balance.
How to use this calculator
- Enter fluid density, displaced volume, gravity and object mass. The net-force comparison is upward buoyancy minus weight.
- Check the labels and units before applying the result to a real task.
- Change one input at a time when comparing scenarios.
Formula and method
Fᵦ = ρfluid Vdisplaced g; weight = m g
- Fᵦ = ρfluid Vdisplaced g; weight = m g
- The displaced volume must match how much fluid the object actually displaces. Stability, shape, fluid motion and compressibility are not modeled.
Worked examples
Worked example
A body displaces 0.01 m³ of water at 1,000 kg/m³, with g = 9.81 m/s².
Buoyant force is 1,000×0.01×9.81 = 98.1 N.
Buoyant force is 1,000×0.01×9.81 = 98.1 N.
Understanding the result
Archimedes’ principle estimates the upward buoyant force exerted by a fluid on a displaced volume. Comparing buoyancy with the object’s weight offers a simple force balance.
The displaced volume must match how much fluid the object actually displaces. Stability, shape, fluid motion and compressibility are not modeled.
Important notes
The displaced volume must match how much fluid the object actually displaces. Stability, shape, fluid motion and compressibility are not modeled.
Displayed values are rounded for readability; retain appropriate precision when continuing a calculation.
Frequently asked questions
Does buoyant force depend on object mass?
The buoyant force depends on fluid density, displaced volume and gravity. Object mass is used here only to compare buoyancy with weight.
What volume should I enter for a floating object?
Use the submerged volume that displaces fluid, not necessarily the object’s total volume.
Does positive net force guarantee that an object floats?
No. The simple comparison helps reason about forces but does not model changing submerged volume, motion, constraints or fluid dynamics.
Related calculators
- Centripetal Force Calculator — Calculate the inward force and acceleration needed for circular motion from mass, speed and radius.
- Force Calculator — Calculate force from mass and acceleration.
- Spring Force Calculator — Calculate ideal spring force magnitude from a spring constant and displacement using Hooke’s law.
- Gravitational Force Calculator — Estimate the mutual gravitational attraction between two masses separated by a center-to-center distance.
- Volume Calculator — Calculate the volume of a rectangular box, cylinder, or sphere.
- Conductor Resistance from Resistivity Calculator — Estimate conductor resistance from material resistivity, length and cross-sectional area with unit conversion.
Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
- How to Calculate Percent Error — Learn the percent error formula and how to compare an experimental value with a reference or accepted value.
- How to Calculate Salary from an Hourly Rate — Convert hourly pay into weekly, monthly, and annual estimates and understand the assumptions behind the result.
- Density — Understand density, mass, volume, and the basic density formula used in science and measurement.
This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.