Joules to Calories Converter
Type a value in joules to see it in gram calories as you type, with the exact formula and a reference chart.
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How this was calculated
- 1 gram calorie = 4.184 joules
- 1,000 ÷ 4.184 = 239.00574 cal
| J | cal |
|---|---|
| 1 J | 0.239006 cal |
| 4.184 J | 1 cal |
| 10 J | 2.39006 cal |
| 50 J | 11.9503 cal |
| 100 J | 23.9006 cal |
| 250 J | 59.7514 cal |
| 418.4 J | 100 cal |
| 500 J | 119.503 cal |
| 1,000 J | 239.006 cal |
| 2,000 J | 478.011 cal |
| 4,184 J | 1,000 cal |
| 5,000 J | 1,195.03 cal |
| 10,000 J | 2,390.06 cal |
| 100,000 J | 23,900.6 cal |
| cal | J |
|---|---|
| 0.2 cal | 0.8368 J |
| 0.5 cal | 2.092 J |
| 1 cal | 4.184 J |
| 2 cal | 8.368 J |
| 5 cal | 20.92 J |
| 10 cal | 41.84 J |
| 20 cal | 83.68 J |
| 50 cal | 209.2 J |
| 100 cal | 418.4 J |
| 200 cal | 836.8 J |
| 500 cal | 2,092 J |
| 1,000 cal | 4,184 J |
How to convert joules to gram calories
1 joule = 0.2390057361 gram calories. To convert joules to gram calories, divide by 4.184 (or multiply by 0.2390057361). The joule is the SI unit of energy, one newton-meter. A gram calorie (thermochemical calorie, written with a lowercase c) is exactly 4.184 J; 1,000 of them make one food Calorie (kilocalorie).
Worked examples
- 100 joules = 23.9006 cal (100 ÷ 4.184)
- 1,000 joules = 239.006 cal (1,000 ÷ 4.184)
- 4,184 joules = 1,000 cal (4,184 ÷ 4.184)
Where this conversion comes up
Joules are used for physics and electrical energy; gram calories for chemistry, physics and calorimetry. Calorimetry problems measure heat in joules and ask for calories, using the thermochemical calorie: exactly 4.184 J is the energy that warms 1 g of water by about 1 °C. This page converts to small gram calories (cal). Food labels use the kilocalorie (Calorie, kcal), which is 1,000 times larger, so 4,184 J is 1,000 cal but only 1 food Calorie.
Quick estimate
Divide by 4 and subtract 4%: 1,000 J ≈ 239 cal.
Common mistakes
- Multiplying instead of dividing. A gram calorie is larger than a joule, so the number of gram calories must come out smaller: 100 joules = 23.9006 cal.
- Rounding too early. Keep the full factor until the last step; rounding 0.239 to 0.24 first puts large values noticeably off.
Related energy converters: kj to calories, kcal to kj, kj to kcal, kwh to mwh, kj to j, j to kj.
Frequently asked questions
How do you convert joules to gram calories?
Multiply the joules by 0.2390057361 (or divide by 4.184). For example, 1,000 joules is 239.006 gram calories.
How many gram calories are in one joule?
One joule is 0.2390057361 gram calories. The joule is the SI unit of energy, one newton-meter.
What is 4,184 joules in gram calories?
4,184 joules is 1,000 gram calories.
Is there a quick way to estimate joules to gram calories?
Divide by 4 and subtract 4%: 1,000 J ≈ 239 cal.