Calories to Joules Conversion Chart
Quick-reference chart converting calories (cal) and kilocalories (kcal) to joules (J). Covers 1 cal to 5,000 kcal — for nutrition, chemistry, and physics applications.
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| Calorie (cal) | Joule (J) |
|---|---|
| 1 cal | 4.184 J |
| 5 cal | 20.92 J |
| 10 cal | 41.84 J |
| 25 cal | 104.6 J |
| 50 cal | 209.2 J |
| 100 cal | 418.4 J |
| 200 cal | 836.8 J |
| 250 cal | 1046 J |
| 500 cal | 2092 J |
| 1000 cal | 4184 J |
| 2000 cal | 8368 J |
| 5000 cal | 20920 J |
| 10000 cal | 41840 J |
| 25000 cal | 104600 J |
| 50000 cal | 209200 J |
| 100000 cal | 418400 J |
| 250000 cal | 1046000 J |
| 500000 cal | 2092000 J |
| 1000000 cal | 4184000 J |
| 2000000 cal | 8368000 J |
| 5000000 cal | 20920000 J |
Conversion Formula
J = cal × 4.184 cal = J ÷ 4.184 1 cal = 4.184 J (thermochemical calorie, exact) Nutrition context: 1 kcal (food Calorie) = 1,000 cal = 4,184 J 100 kcal = 418,400 J = 418.4 kJ 2,000 kcal/day (average diet) = 8,368,000 J = 8.368 MJ 2,500 kcal/day = 10,460,000 J = 10.46 MJ Exercise energy burn (approximate): Walking 1 hr (~4 km): 200–300 kcal = 837–1,255 kJ Running 1 hr (~10 km): 500–700 kcal = 2,092–2,929 kJ Cycling 1 hr (~25 km): 400–600 kcal = 1,674–2,510 kJ
Frequently Asked Questions
How many joules is 100 calories?
100 cal × 4.184 = 418.4 J. Note: this is 100 small calories. 100 food Calories (kcal) = 100,000 cal = 418,400 J. Always confirm whether a value uses small calories or kilocalories (food Calories).
How many joules is 2,000 food Calories (kcal)?
2,000 kcal × 4,184 J/kcal = 8,368,000 J = 8.368 MJ. A 2,000 kcal daily diet is equivalent to about 8.4 megajoules of stored chemical energy in food. For perspective, 1 kWh = 3.6 MJ, so a day's food represents about 2.3 kWh of chemical energy.
What is the joule equivalent of burning 1 pound of fat?
One pound of body fat stores approximately 3,500 kcal = 3,500 × 4,184 = 14,644,000 J ≈ 14.6 MJ. This is the well-known '3,500 calories per pound' figure used in weight management. Achieving a 500 kcal/day deficit (2,092 kJ) creates a pound of fat loss per week.
How are nutrition labels reported in the EU vs. US?
The EU requires food energy to be reported in both kJ and kcal per 100 g (and per portion). The US uses only kcal (called 'Calories' on labels). A US label showing 250 Calories per serving = 250 kcal = 1,046 kJ. The kJ value is about 4.18× the kcal value.
What is the specific heat capacity of water in joules?
The specific heat capacity of liquid water is 4.184 J/g·°C — equivalently, 4,184 J/kg·°C or 4.184 kJ/kg·K. This is why the calorie was defined in terms of water: 1 calorie heats 1 gram of water by exactly 1°C. Water's high specific heat makes it an excellent coolant and climate moderator.
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