Calories to Joules (cal to J) Converter
A 3-way energy converter. Enter a value in any field to instantly convert between **Joules (J)**, **Calories (cal)**, and **Kilocalories (kcal)** (food Calories).
The Difference: Calorie (cal) vs. Calorie (kcal)
The main source of confusion in this conversion is that the word "calorie" is used for two different units of energy. This tool converts both, eliminating the confusion.
- Calorie (cal): This is the "small calorie" or "gram calorie" used in physics and chemistry. It's the energy needed to raise the temperature of 1 gram of water by 1°C.
- Kilocalorie (kcal): This is the "large calorie" or "food Calorie" (with a capital C). It's the unit you see on nutrition labels. 1 kcal = 1,000 cal.
Conversion Formulas
The conversion is based on the international standard for the thermochemical calorie:
From this, all other conversions are derived:
- Joules to Calories:
cal = J / 4.184 - Joules to Kilocalories:
kcal = J / 4184 - Kilocalories to Joules:
J = kcal × 4184
Energy Conversion Chart
| Joules (J) | Calories (cal) | Kilocalories (kcal) |
|---|---|---|
| 1 J | 0.239 cal | 0.000239 kcal |
| 1000 J (1 kJ) | 239.0 cal | 0.239 kcal |
| 4184 J (4.184 kJ) | 1000 cal | 1 kcal |
| 100,000 J (100 kJ) | 23,900 cal | 23.9 kcal |
| 1,000,000 J (1 MJ) | 239,005 cal | 239.0 kcal |
Frequently Asked Questions (FAQ)
What is the formula for calories (cal) to Joules (J)?
The standard scientific formula is: 1 calorie (cal) = 4.184 Joules (J). To convert from calories to Joules, you multiply the calorie value by 4.184.
How many Joules are in a food Calorie (kcal)?
A food Calorie (Cal) is a kilocalorie (kcal), which is 1,000 small calories. Therefore:
1 kcal = 1000 cal × 4.184 J/cal = 4184 Joules (or 4.184 kJ).
Is a Calorie (capital C) a kilocalorie?
Yes. In nutrition, "Calorie" (with a capital C) is a synonym for "kilocalorie" (kcal). 1 Calorie = 1 kcal = 1,000 calories.
Formula (LaTeX) + variables + units
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1 Calorie (cal) = 4.184 Joules (J)
- No variables provided in audit spec.
- CDC — Health topics — cdc.gov · Accessed 2026-01-19
https://www.cdc.gov/ - NIH — Health information — nih.gov · Accessed 2026-01-19
https://www.nih.gov/health-information - WHO — Health topics — who.int · Accessed 2026-01-19
https://www.who.int/health-topics
Last code update: 2026-01-19
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