Joules to Calories Conversion Chart
Quick-reference chart converting joules (J) to calories (cal). Covers 1–100,000 joules — for chemistry, nutrition science, physics experiments, and food energy calculations.
For a custom value not in this chart, use the Energy converter.
| Joule (J) | Calorie (cal) |
|---|---|
| 1 J | 0.239006 cal |
| 5 J | 1.19503 cal |
| 10 J | 2.39006 cal |
| 20 J | 4.78011 cal |
| 50 J | 11.9503 cal |
| 100 J | 23.9006 cal |
| 200 J | 47.8011 cal |
| 418.4 J | 100 cal |
| 500 J | 119.503 cal |
| 1000 J | 239.006 cal |
| 2000 J | 478.011 cal |
| 4184 J | 1000 cal |
| 5000 J | 1195.03 cal |
| 10000 J | 2390.06 cal |
| 20000 J | 4780.11 cal |
| 50000 J | 11950.3 cal |
| 100000 J | 23900.6 cal |
Conversion Formula
cal = J ÷ 4.184
J = cal × 4.184
1 calorie (thermochemical) = 4.184 J (exact)
1 joule = 0.239006 cal
IMPORTANT: 'food Calories' (capital C) = kilocalories:
1 kcal = 1,000 cal = 4,184 J
200 food Calories = 200 kcal = 836,800 J
Nutrition reference:
1 g carbohydrate = 4 kcal = 16,736 J
1 g protein = 4 kcal = 16,736 J
1 g fat = 9 kcal = 37,656 J
1 g alcohol = 7 kcal = 29,288 J
Physics reference:
4,184 J = 1 kcal (energy to heat 1 L water by 1°C)Frequently Asked Questions
How many calories is 1 joule?
1 joule = 0.239006 thermochemical calories. The thermochemical calorie (cal) is defined as exactly 4.184 joules — the energy needed to heat 1 gram of water by 1°C. This is the small calorie used in chemistry.
What is the difference between a calorie and a food Calorie?
A small calorie (cal) = 4.184 J. A food Calorie (Cal, with capital C) = 1 kilocalorie (kcal) = 1,000 cal = 4,184 J. Food labels in the US use 'Calories' (capital C) to mean kilocalories. A 200-calorie snack bar actually contains 200 kcal = 200,000 small calories = 836,800 joules.
How many joules is 1,000 food Calories (kcal)?
1,000 kcal × 4,184 J/kcal = 4,184,000 J (4.184 MJ). A moderately active adult burns approximately 2,000–2,500 kcal/day = 8.37–10.46 MJ. Running a marathon consumes approximately 2,600 kcal = 10.88 MJ.
Why is energy in food measured in calories instead of joules?
Calorie-based food labeling predates SI unit standardization and is deeply embedded in nutrition science and public health. The USDA, FDA, and equivalent agencies in many countries continue to use kcal for food energy. Some countries (EU, Australia) label food in both kcal and kJ to facilitate comparison.
How many joules does it take to heat water?
Heating 1 gram of water by 1°C requires 4.184 J (= 1 thermochemical calorie). Heating 1 liter (1,000 g) of water from 20°C to 100°C requires: 1,000 g × 80°C × 4.184 J/g°C = 334,720 J = 334.7 kJ = 79,962 cal ≈ 80 kcal.
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Use the interactive converter →All conversion values are calculated using internationally recognized conversion factors. Results are provided for general informational purposes — verify critical values independently. Read our full disclaimer.