1 kcal = 4.184 kJ
1 kilocalorie equals 4.184 kilojoules. To convert kilocalories to kilojoules, multiply the kilocalorie value by 4.184. For quick reference: 1 kcal = 4.184 kJ, 5 kcal = 20.92 kJ, 10 kcal = 41.84 kJ, 100 kcal = 418.4 kJ.
Kilojoules = Kilocalories × 4.184Start with your value in kilocalories.
Multiply the kilocalorie value by 4.184. This is the exact conversion factor from kilocalories to kilojoules.
The product is your value in kilojoules. For example, 5 kcal × 4.184 = 20.92 kJ.
The exact factor from kilocalories to kilojoules is 4.184.
Kilojoules = Kilocalories × 4.184
Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 0.001 kcal | 0.004184 kJ |
| 0.01 kcal | 0.04184 kJ |
| 0.1 kcal | 0.4184 kJ |
| 0.5 kcal | 2.092 kJ |
| 1 kcal | 4.184 kJ |
| 1.5 kcal | 6.276 kJ |
| 2 kcal | 8.368 kJ |
| 5 kcal | 20.92 kJ |
| 10 kcal | 41.84 kJ |
| 20 kcal | 83.68 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 200 kcal | 836.8 kJ |
| 250 kcal | 1046 kJ |
| 500 kcal | 2092 kJ |
| 1000 kcal | 4184 kJ |
| 2000 kcal | 8368 kJ |
| 2500 kcal | 10460 kJ |
| 3600 kcal | 15062 kJ |
| 5000 kcal | 20920 kJ |
| 7500 kcal | 31380 kJ |
| 10000 kcal | 41840 kJ |
| 25000 kcal | 104600 kJ |
| 50000 kcal | 209200 kJ |
| 100000 kcal | 418400 kJ |
| 250000 kcal | 1046000 kJ |
| 500000 kcal | 2092000 kJ |
| 1000000 kcal | 4184000 kJ |
| 2000000 kcal | 8368000 kJ |
| 3600000 kcal | 15062400 kJ |
| 5000000 kcal | 20920000 kJ |
| 10000000 kcal | 41840000 kJ |
| 25000000 kcal | 104600000 kJ |
| 50000000 kcal | 209200000 kJ |
| 100000000 kcal | 418400000 kJ |
| 250000000 kcal | 1046000000 kJ |
| 500000000 kcal | 2092000000 kJ |
| 1000000000 kcal | 4184000000 kJ |
| 2000000000 kcal | 8368000000 kJ |
| 5000000000 kcal | 20920000000 kJ |
| 10000000000 kcal | 41840000000 kJ |
| 20000000000 kcal | 83680000000 kJ |
| 50000000000 kcal | 209200000000 kJ |
| 100000000000 kcal | 418400000000 kJ |
| 1000000000000 kcal | 4184000000000 kJ |
| 10000000000000 kcal | 41840000000000 kJ |
| 100000000000000 kcal | 418400000000000 kJ |
| 1000000000000000 kcal | 4.1840 × 10^15 kJ |
| 10000000000000000 kcal | 4.1840 × 10^16 kJ |
| 100000000000000000 kcal | 4.1840 × 10^17 kJ |
A medium apple has about 95 kcal. An adult's daily energy need is roughly 2,000–2,500 kcal. In kilojoules, that gives you: 1 kcal = 4.184 kJ, 10 kcal = 41.84 kJ, 100 kcal = 418.4 kJ.
The kilocalorie (kcal) equals exactly 4,184 joules — 1,000 small calories. This is the 'Calorie' (capital C) printed on US nutrition labels: when a food package says '250 Calories', it means 250 kcal. Outside the US, food energy is usually labeled in kJ as well.
The kilojoule (kJ) equals exactly 1,000 joules. It is the standard unit on EU and many non-US nutrition labels — 1 dietary calorie ≈ 4.184 kJ. It also appears in industrial-process specifications and energy-storage ratings.