Converters
Energy Converter
Convert between every energy unit — instant, accurate, and free.
0.001
1 J = 0.001 kJ
Common conversions
From 1 joules- Kilojoules (kJ)0.001
- Calories (cal)0.239006
- Kilocalories (kcal)0.000239006
- Watt-hours (Wh)0.000277778
- Kilowatt-hours (kWh)2.7778e-7
- BTU (BTU)0.000947813
- Electronvolts (eV)6.2415e+18
How it works
Every conversion in energy normalizes through a base unit (joules), then scales to the target unit.
The Energy Converter handles 8 units and every combination between them. Pick a source unit, a target unit, and enter a value — the result updates instantly with high-precision arithmetic.
Frequently asked
Which energy units are supported?
Joule (J), Kilojoule (kJ), Calorie (cal), Kilocalorie (kcal), Watt-hour (Wh), Kilowatt-hour (kWh), BTU (BTU), Electronvolt (eV).
How accurate are the conversions?
We use internationally standardized conversion factors and JavaScript double-precision arithmetic, giving accurate results to at least 12 significant figures for most values.
Do I need an internet connection?
No. Once the page loads, every calculation runs locally in your browser. Nothing is sent to a server.
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