Online energy converter
Energy Converter converts energy across joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, and foot-pounds. Choose the source and target units, then enter any positive, negative, or decimal value.
Results update immediately and the swap control reverses the conversion in one click. All calculations run locally in your browser.
How to use this tool
- 1Enter the value you want to convert.
- 2Choose the source unit.
- 3Choose the target unit.
- 4Copy or use the instant result.
Multiple units
Convert common energy units from one clean interface.
Instant result
The answer updates as soon as a value or unit changes.
Accurate factors
Conversions use recognized standard factors and formulas.
Frequently asked questions
Which units does this Energy Converter support?+
It supports joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, and foot-pounds.
Can I enter decimal or negative values?+
Yes. Decimal and negative values are accepted whenever they make sense for the selected units.
How do I reverse a conversion?+
Select the swap button between the From and To fields to reverse both units.
Are values sent to a server?+
No. The conversion happens locally in your browser and the entered values are not uploaded.