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Kilocalories to Joules

Enter an amount in kilocalories, choose the kind of calorie it is measured in, and read the same energy in joules. One food calorie (Cal) is 1 kcal, which is 4184 J.

What this page converts

It changes an amount given in kilocalories (kcal) into the same energy in joules (J). A select sets which kind of calorie your amount uses: Thermochemical/food calorie at 4.184 J, International calorie at 4.1868 J, 15°C calorie at about 4.1855 J, or 20°C calorie at about 4.182 J.

Type the kilocalories into the number field, choose the calorie kind and press Convert; the result appears in a card below the button. Copy writes the result and its unit to the clipboard, and Clear resets the form.

Kilocalories to joules formula

Joules = kilocalories × the factor for the calorie kind you picked. Those factors are 1 kcal = 4184 J for the thermochemical calorie, 1 kcal = 4186.8 J for the international calorie, 1 kcal = 4185.5 J for the 15°C calorie and 1 kcal = 4182 J for the 20°C calorie.

One thermochemical calorie is exactly 4.184 J by definition, and one international calorie is exactly 4.1868 J, so those two factors are exact. The 15°C calorie is about 4.1855 J and the 20°C calorie about 4.182 J, so their factors are close rather than exact.

Two readings straight from the table below: 5 kcal is 20920 J and 100 kcal is 418400 J, both on the Thermochemical/food calorie.