Quick guide
How to use this calculator
- Enter the value exactly as recorded, then choose its source unit and the unit you need.
- Check regional and technical qualifiers in the unit names. US and Imperial gallons, force and mass, absolute temperatures and temperature differences, and decimal and binary data prefixes are deliberately separate.
- Use the selected result first, then open the common-equivalents table when you need to compare several standards without re-entering the value.
Calculation method
How the energy converter works
The entered energy is converted once to the canonical joule basis and then from that basis to the selected output unit.
Calories are thermochemical calories and BTU are International Table BTU; food Calories are kilocalories.
Worked example
Energy example
One kilowatt-hour equals exactly 3.6 megajoules.
source value × source-to-joule relationship → canonical joule value → destination-unit relationship
Supported inputs
Precision and limits
Unit convention
Calories are thermochemical calories and BTU are International Table BTU; food Calories are kilocalories.
Precision
Definitions and exact conventional factors are retained internally where available. Display formatting uses up to 12 significant digits; very large or small results use scientific notation. Do not treat displayed digits as measurement accuracy beyond the source value.
Quantity boundary
This page converts energy. It does not infer a different physical quantity, material property, environmental condition, exchange rate, calendar rule, or regulatory value needed to make a cross-quantity conversion.
Privacy
Entered values and converted results stay in this browser and are not sent to analytics or third parties.
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