How many kcal is 1 kJ?

0.239 kcal. Put the other way, 4.184 kJ make one kilocalorie.

What is 8,700 kJ in calories?

About 2,079 kcal. 8,700 kJ is the average adult daily intake used on Australian labels.

Why is the kJ number on my snack four times larger than the calories?

Because a kilojoule is a much smaller unit. Each kilocalorie equals 4.184 kJ, so the kJ figure is always about four times larger.

Can I divide kilojoules by 4 instead of 4.184?

For a rough idea, yes. The answer comes out about 4.6% too high, which adds up to roughly 90 kcal over a full day of eating.

Kilojoules to Kilocalories

A kilojoule is about 0.239 kilocalories, so you divide kJ by 4.184 to get kcal: 1,000 kJ is 239 kcal and 8,700 kJ is 2,079 kcal. Type a kilojoule value below to see it in food calories.

Kilojoules to kilocalories at a glance

Seven values you meet most often. The tables and the converter handle everything in between.

1 kJ
0.239006 kcal
2 kJ
0.478011 kcal
5 kJ
1.19503 kcal
10 kJ
2.39006 kcal
20 kJ
4.78011 kcal
50 kJ
11.9503 kcal
100 kJ
23.9006 kcal

Shopping with kilojoule labels

Australian and New Zealand food is labeled in kilojoules, and menu boards at large chains show kJ too. A meat pie listed at 1,900 kJ is about 454 kcal, a 600 mL soft drink near 1,000 kJ is about 240 kcal, and a 120 kJ diet drink is under 30 kcal. Dividing by 4 gives a quick estimate that runs about 4.6% high, which is fine for a menu and not for a diet log.

European labels print both units, but the kJ figure is listed first, so travelers sometimes record the bigger number by mistake. If a value looks four times larger than you expected, you are probably reading kilojoules.

Why some labels do not match 4.184

Labels do not calculate kcal from kJ. Both are worked out from the food's composition using fixed factors per nutrient. In the EU these are 37 kJ or 9 kcal per gram of fat, 17 kJ or 4 kcal per gram of protein or carbohydrate, and 29 kJ or 7 kcal per gram of alcohol. Since 37/9 is 4.11 and 17/4 is 4.25, a fatty food can show a kJ/kcal ratio below 4.184 and a sugary one a ratio above it.

So if you convert a label's kJ with the exact factor, the result may differ from the printed kcal by a few percent. Neither number is wrong; they come from rounded nutrient factors. When both are printed, trust the one in the unit you are tracking.

Kilojoules beyond food

Scientific papers, sports nutrition and chemistry report energy in joules and kilojoules, because the joule is the SI unit. A 60 kg person walking for an hour spends around 1,000 kJ, roughly 240 kcal. For small chemistry calories, see calories to joules; the forward direction is on kcal to kJ.

Frequently asked questions

How many kcal is 1 kJ?: 0.239 kcal. Put the other way, 4.184 kJ make one kilocalorie.
What is 8,700 kJ in calories?: About 2,079 kcal. 8,700 kJ is the average adult daily intake used on Australian labels.
Why is the kJ number on my snack four times larger than the calories?: Because a kilojoule is a much smaller unit. Each kilocalorie equals 4.184 kJ, so the kJ figure is always about four times larger.
Can I divide kilojoules by 4 instead of 4.184?: For a rough idea, yes. The answer comes out about 4.6% too high, which adds up to roughly 90 kcal over a full day of eating.