Joule to Calorie Converter

1 J ≈ 0.239 cal (small) ≈ 0.000239 kcal (food calorie).

Inputs

Result

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General calculation reads

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Scientific calculator (Casio fx-991EX)
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How to use this calculator

  • Enter joules.
  • Pick output (small cal or food kcal).
  • Read converted value.

About this calculator

Inverse of calorie-to-joule. 1 kJ ≈ 239 small cal ≈ 0.239 kcal. Some example energies: a baseball thrown at 90 mph has ~135 J kinetic energy, equivalent to about 32 calories (small) or 0.032 food Calories.

Frequently asked

Is the kcal/Calorie thing really a problem?+
Mostly resolved by context — nutrition uses kcal/Cal, physics uses J or cal. Watch for "calories" (lowercase) on energy bars — usually kcal in disguise.
kJ on lab equipment?+
Yes — physics, chemistry, and engineering all use kJ. Multiply by 0.239 to get small calories.
Quick mental math?+
4 J ≈ 1 small cal. 4 kJ ≈ 1 kcal.
Watt-seconds vs Joules?+
Same thing. 1 W·s = 1 J.
Why might my measurement differ slightly?+
Different "calorie" definitions exist; thermochemical (4.184) is the most common. If you see 4.1868 (IT calorie), you're using a different convention.

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