Energy Converter

Convert between joules, calories, watt-hours, BTU, and more. Enter a value and pick the units.

Converted
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In the target unit.

Usage Tip

Useful anchors: 1 kWh ≈ 3412 BTU, 1 kcal = 4184 J, 1 BTU ≈ 1055 J.

THE MATH
Convert to a base unit, then to the target:
result = value × (from factor ÷ to factor)
Energy converts through joules. Electrical billing uses kWh; food labels use kcal (the food Calorie); heating and cooling often use BTU.
A food Calorie (capital C) is one kilocalorie.
The food Calorie is a kilocalorie — a 100 Calorie snack is 100 kcal = 418,400 J.
1 kWh (a unit of electricity) = 3.6 MJ ≈ 3412 BTU.
BTU is common for heating, cooling, and appliance ratings.
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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.