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Calories to Joules Converter

Pick the kind of calorie you have, type the amount, and read off the same energy in joules. Three kinds are covered: the small thermochemical calorie, the small 15°C calorie, and the large food calorie.

What this tool does

This tool converts an amount in calories into the matching amount in joules. It has one number field and a select for the kind of unit: the small thermochemical calorie (cal) at 4.184 J, the small 15°C calorie at about 4.1855 J, and the large food calorie (Cal) at 4184 J.

Nothing is worked out until you press Convert, and the answer then shows in a card below the button. Copy puts the result and its unit on your clipboard, Clear puts the form back to empty, and the whole calculation stays in your browser.

Calories to joules formula

Multiply the calories by the factor for the kind you chose: 1 cal = 4.184 J for the thermochemical calorie, 1 cal ≈ 4.1855 J for the 15°C calorie, and 1 Cal = 4184 J for the food calorie, which is 1 kcal. The thermochemical figure is exact by definition; the 15°C figure is a rounded one.

Reading down the table for the thermochemical calorie: 1 cal is 4.184 J, 5 cal is 20.92 J, 10 cal is 41.84 J, 100 cal is 418.4 J, and 1000 cal is 4184 J.