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Energy Converter

Convert between joules, calories, BTU, kWh, and more.

1 kcal = 4.184 kJ

Kilocalories (food Cal) (kcal)Kilojoules (kJ)
14.184
28.368
520.92
1041.84
1562.76
2083.68
25104.6
50209.2
75313.8
100418.4
150627.6
200836.8
2501,046
5002,092
1,0004,184

Energy Conversion Reference

FromTo
1 kilowatt-hour (kWh)3,600,000 J / 3,412 BTU
1 calorie (cal)4.184 joules
1 food Calorie (kcal)4,184 J / 1,000 calories
1 BTU1,055 joules

Calories vs Kilocalories

When food packaging says "200 Calories," it actually means 200 kilocalories (kcal) — not the scientific calorie used in chemistry. The food Calorie (with a capital C) equals 1 kcal, which equals 1,000 small calories. This naming convention causes endless confusion.

In scientific contexts, use joules (J) or kilojoules (kJ) for energy to avoid ambiguity. A food Calorie is about 4.184 kJ. Your daily energy intake of 2,000 food Calories is roughly 8,368 kJ.