Joules to Calories Converter: Fast & Simple

Which "calorie" this is

This converter uses the small calorie (gram calorie, symbol "cal") — the energy needed to raise 1 gram of water by 1°C — not the "Calorie" (kilocalorie, kcal) printed on nutrition labels. 1 small calorie = 4.184 joules, so 1 joule = 1/4.184 = 0.239 calories, which is the exact factor the script multiplies by.

Worked example

100 joules × 0.239 = 23.9000 calories (small calories), displayed to four decimal places.

Don't confuse this with food energy

Nutrition labels use the food Calorie (kcal), which is 1,000 small calories — so 100 joules is only 0.0239 food Calories, not 23.9. If you're converting joules to the Calorie count on a food label, divide the joules figure by 4184 instead of multiplying by 0.239.

Reference points