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Energy Converter
Joule, calorie, kWh, BTU and electronvolt conversions.
Best for: Use it for electricity bills (kWh), food energy (kcal), heating (BTU) or physics work.
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How it's calculated & sources
The Energy Converter uses the standard, deterministic formula, so the same inputs always produce the same result. It runs entirely in your browser, so your inputs are never uploaded. Last reviewed June 2026.
Free & no sign-up · runs entirely in your browser. Results are estimates for general information, not professional advice — verify important decisions with a qualified expert. Last reviewed June 2026.
How it works
Joule is the SI energy unit. 1 kWh = 3.6 × 10⁶ J. 1 kcal = 4,184 J.
Example
1 kWh = 3,600 kJ ≈ 860 kcal ≈ 3,412 BTU.
Frequently asked questions
Is conversion real-time?+
Yes — values update instantly as you type in either field, with full bidirectional input.
Where does the energy reference come from?+
All factors are SI-anchored using internationally accepted conversions.
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