Unit Converters · Browser · Free

Kilocalories to Kilojoules (kcal to kJ)

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

About this converter

The converter changes an amount given in kilocalories into kilojoules. One number field takes the amount, and a select chooses the kind of calorie, since the definitions use slightly different factors.

A thermochemical calorie is exactly 4.184 J, so 1 kcal equals 4.184 kJ. An international calorie is exactly 4.1868 J, so 1 kcal equals 4.1868 kJ. The 15°C calorie is about 4.1855 J and the 20°C calorie about 4.182 J.

The result is worked out only when you press Convert, and it appears in a card below the button. Copy writes the result and its unit to the clipboard, and Clear resets the form. Everything runs in the browser and nothing is uploaded.

Kilocalories to kilojoules formula

kilojoules = kilocalories × 4.184 for the thermochemical or food calorie, × 4.1868 for the international calorie, × about 4.1855 for the 15°C calorie and × about 4.182 for the 20°C calorie.

Taking a row from the table below: 10 kcal × 4.184 gives the listed 41.84 kJ, and 1000 kcal is listed as 4184 kJ.