Supported units
Convert between joule (J), kilojoule (kJ), watt-hour (Wh), kilowatt-hour (kWh), British thermal unit (BTU IT), calorie (cal th), kilocalorie (kcal), and electron-volt (eV). Exact relationships are used, including 1 kWh = 3,600,000 J, 1 BTU (IT) = 1055.05585262 J, and 1 cal(th) = 4.184 J.
Popular pairs
- J <-> kWh
- kWh <-> BTU (IT)
- cal(th) <-> kcal
- J <-> eV
- J <-> Wh
How to use
Pick your from/to units using the search boxes, enter a value, and the result updates instantly. Use the copy button to grab the output.
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Energy Converter FAQ
Are the conversions exact?
Yes. We use exact definitions such as 1 kWh = 3,600,000 J, 1 BTU (IT) = 1055.05585262 J, and 1 cal(th) = 4.184 J.
Can I convert kWh to BTU and back?
Yes. Enter your value in kWh and select BTU (IT) as the target (or vice versa); results update instantly as you type.
Does this handle very small or very large energy values?
Yes. You can convert down to electron-volts or up to kilowatt-hours with high precision using Decimal arithmetic.