1 cal = 0.004184 kJ
1 calorie equals 0.004184 kilojoules. To convert calories to kilojoules, multiply the calorie value by 0.004184. For quick reference: 1 cal = 0.004184 kJ, 5 cal = 0.02092 kJ, 10 cal = 0.04184 kJ, 100 cal = 0.4184 kJ.
Kilojoules = Calories × 0.004184Start with your value in calories.
Multiply the calorie value by 0.004184. This is the exact conversion factor from calories to kilojoules.
The product is your value in kilojoules. For example, 5 cal × 0.004184 = 0.02092 kJ.
The exact factor from calories to kilojoules is 0.004184.
Kilojoules = Calories × 0.004184
Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.
| Calories (cal) | Kilojoules (kJ) |
|---|---|
| 0.001 cal | 4.1840 × 10^−6 kJ |
| 0.01 cal | 4.1840 × 10^−5 kJ |
| 0.1 cal | 0.0004184 kJ |
| 0.5 cal | 0.002092 kJ |
| 1 cal | 0.004184 kJ |
| 1.5 cal | 0.006276 kJ |
| 2 cal | 0.008368 kJ |
| 5 cal | 0.02092 kJ |
| 10 cal | 0.04184 kJ |
| 20 cal | 0.08368 kJ |
| 50 cal | 0.2092 kJ |
| 100 cal | 0.4184 kJ |
| 200 cal | 0.8368 kJ |
| 250 cal | 1.046 kJ |
| 500 cal | 2.092 kJ |
| 1000 cal | 4.184 kJ |
| 2000 cal | 8.368 kJ |
| 2500 cal | 10.46 kJ |
| 3600 cal | 15.062 kJ |
| 5000 cal | 20.92 kJ |
| 7500 cal | 31.38 kJ |
| 10000 cal | 41.84 kJ |
| 25000 cal | 104.6 kJ |
| 50000 cal | 209.2 kJ |
| 100000 cal | 418.4 kJ |
| 250000 cal | 1046 kJ |
| 500000 cal | 2092 kJ |
| 1000000 cal | 4184 kJ |
| 2000000 cal | 8368 kJ |
| 3600000 cal | 15062 kJ |
| 5000000 cal | 20920 kJ |
| 10000000 cal | 41840 kJ |
| 25000000 cal | 104600 kJ |
| 50000000 cal | 209200 kJ |
| 100000000 cal | 418400 kJ |
| 250000000 cal | 1046000 kJ |
| 500000000 cal | 2092000 kJ |
| 1000000000 cal | 4184000 kJ |
| 2000000000 cal | 8368000 kJ |
| 5000000000 cal | 20920000 kJ |
| 10000000000 cal | 41840000 kJ |
| 20000000000 cal | 83680000 kJ |
| 50000000000 cal | 209200000 kJ |
| 100000000000 cal | 418400000 kJ |
| 1000000000000 cal | 4184000000 kJ |
| 10000000000000 cal | 41840000000 kJ |
| 100000000000000 cal | 418400000000 kJ |
| 1000000000000000 cal | 4184000000000 kJ |
| 10000000000000000 cal | 41840000000000 kJ |
| 100000000000000000 cal | 418400000000000 kJ |
Burning a single dietary calorie of fat releases about 4.184 kJ of heat. A wooden match releases roughly 1,000 small calories.
Convertitive uses the thermochemical (small) calorie, defined as exactly 4.184 joules — the energy needed to raise 1 g of water by 1 °C. Do not confuse it with the large calorie (kcal) used on US nutrition labels, which is 1,000 of these small calories.
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.