Convert kJ to kcal

1 kJ = 0.239 kcal: the formula

To convert kJ to kcal, divide by 4.184: kcal = kJ ÷ 4.184, the same as multiplying by 0.239006. Example: a muesli bar in Australia lists 920 kJ per serve. That is 920 ÷ 4.184 = 219.89 kcal, or 220 Calories in US terms.

The tool opens on 100 kJ to kcal, which is 23.9006 kcal. Type your figure in "Value" and the answer follows each keystroke. The "Formula:" line shows 1 kJ = 0.239006 kcal, the "In every unit" table adds joules, calories and watt-hours, and ⇄ "Swap units" switches to kcal to kJ.

kJ to kcal chart

Where kilojoules turn up

Australia and New Zealand

Labels and many menus show energy in kJ, sometimes with no kcal at all. Fast-food chains in several Australian states must display kJ on the menu board, next to the 8,700 kJ daily reference. A 2,400 kJ burger meal is 573.6 kcal.

Cycling with a power meter

Power meters count work done at the pedals in kJ. A 1,000 kJ ride is 239 kcal of mechanical work, but your body spent about four times that, close to 1,000 kcal, because muscles turn only about a quarter of food energy into motion. That is why riders treat kJ on the head unit as roughly equal to kcal burned.

Mental math

Divide by 4, then take off 4%. For 1,200 kJ: 1,200 ÷ 4 = 300, minus 12, gives 288 kcal against 286.81 exactly. Dividing by 4 alone reads 4.6% high.

Frequently asked questions

Why do UK labels pair 8,400 kJ with 2,000 kcal?

Both are reference values set in law and rounded separately. The exact conversion of 8,400 kJ is 2,007.65 kcal.

How many kcal is 100 kJ?

23.90 kcal. And 1,000 kJ is 239.01 kcal.

Which one is the official unit?

The joule is the SI unit of energy. The calorie is outside the SI but still allowed for food, which is why packs show both.