Quick answer
1,000 kcal = 4,184 kJ. Multiply 1,000 by 4.184 to check: 1,000 × 4.184 = 4,184.
How to convert 1000 calories to kJ
- Start with 1,000 calories (kcal).
- Multiply by 4.184: 1,000 × 4.184 = 4,184 kJ.
- For joules, multiply by 4,184: that gives 4,184,000 J.
You may also see this searched as 1000 cal to kj or 1000 calories to kilojoules. A small calorie (cal) is different: 1,000 cal is 4.184 kJ. Food labels almost always mean kcal. See the calories to kJ converter for more.
1000 kcal in context
- 48% of the 8,700 kJ average-adult reference day on Australian and New Zealand labels.
- 50% of a 2,000 kcal reference day, as used on EU and US labels.
- Reference intakes are label conventions. Your own needs depend on age, sex, size and activity. See how many kJ you should eat per day.
Good to know
1,000 kcal is 4,184 kJ, or 4.184 MJ, and half of a 2,000 kcal day.
Nearby conversions
| Calories (kcal) | Kilojoules (kJ) |
|---|---|
| 250 kcal | 1,046 kJ |
| 500 kcal | 2,092 kJ |
| 1,000 kcal | 4,184 kJ |
| 1,500 kcal | 6,276 kJ |
| 2,000 kcal | 8,368 kJ |
Browse all popular conversions or the calories to kJ chart.
Frequently asked questions
How many kJ is 1000 calories?
1000 calories (kcal) is 4,184 kJ. Multiply 1000 by 4.184 to check.
How many joules is 1000 kcal?
1000 kcal is 4,184,000 J, since 1 kcal is 4,184 J.
What percentage of a daily intake is 1000 kcal?
About 50% of a 2,000 kcal reference day, or about 48% of the 8,700 kJ reference day.
Last updated 11 Oct 2026. How we calculate.