Unit Converter
The Unit Converter helps convert measurements between compatible units. It can be used for length, mass, volume, temperature, speed, area, and other common measurement systems, depending on the units supported by the calculator.
How to use this calculator
- Select the type of measurement you want to convert.
- Choose the original unit.
- Enter the value you want to convert.
- Choose the destination unit and review the converted result.
Unit conversion methodology
Converted value = original value × conversion factor
- Most unit conversions can be represented using a conversion factor between the source and destination units.
- The conversion factor depends on the measurement category. A length conversion, for example, uses a different relationship from a mass or temperature conversion.
- Temperature conversions require special formulas because their scales have different zero points, so they are not always simple multiplication.
Worked examples
Example: kilometres to miles
A distance of 10 kilometres can be converted to miles using the appropriate length conversion factor.
The converted value represents the same physical distance in miles.
Example: kilograms to pounds
A mass entered in kilograms can be converted to pounds without changing the underlying quantity being measured.
The calculator expresses the same mass using the selected unit.
Understanding the result
A conversion changes the way a measurement is expressed; it does not change the underlying physical quantity.
Unit systems can use different conventions. For example, metric and imperial systems use different standard units for many measurements.
Rounding can make a displayed converted value slightly different from the full-precision mathematical result.
Important notes
Make sure the source and destination units measure the same physical quantity.
Check whether your application requires a particular rounding precision.
For engineering, scientific, medical, or legal applications, verify critical conversions against the required standard or reference.
Frequently asked questions
What is a conversion factor?
A conversion factor is a numerical relationship used to express the same quantity in a different unit.
Does converting units change the actual amount?
No. A correct unit conversion changes the representation of a quantity, not the underlying quantity itself.
Why can converted results have decimals?
Many units do not have whole-number relationships. Converting between them can therefore produce a decimal result.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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What the all-purpose unit converter can convert
Use this unit converter when you need to switch between common measurements without opening a separate page for each pair. Supported groups include length, weight, volume, speed, digital storage, and temperature. Choose units from the same measurement group so the result represents a valid conversion.
Common conversion examples
- 1 mile = 1.609344 kilometers. See the miles to kilometers converter.
- 1 inch = 2.54 centimeters. Use the inches to centimeters converter.
- 1 kilogram is approximately 2.20462262 pounds. Use the kilograms to pounds converter.
- 1 US liquid gallon = 3.785411784 liters. Use the gallons to liters converter.
Precision and unit choice
Conversion factors can be exact by definition or depend on the chosen unit convention. In particular, US and Imperial gallons differ, so confirm which gallon definition a source uses before comparing volumes. Keep additional decimal places during intermediate calculations and round only when you present the final result at a precision suitable for the task.
For a focused, one-direction conversion with worked reference values, browse the unit-converter library. The library includes specific pages for popular measurement pairs, each with its formula and examples.
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.