UnitConCalories to Joules Converter
Convert dietary Calories (kilocalories) to joules for nutrition science, exercise physiology, and converting food energy values to SI units. The dietary Calorie (capital C) equals one kilocalorie.
Formula
Multiply kilocalories by 4184 to get joules. To reverse, divide joules by 4184 to get kilocalories.
Quick reference
| Kilocalorie (kcal) | Joule (J) |
|---|---|
| 100 | 418,400 |
| 200 | 836,800 |
| 300 | 1,255,200 |
| 500 | 2,092,000 |
| 1000 | 4,184,000 |
| 1500 | 6,276,000 |
| 2000 | 8,368,000 |
| 2500 | 10,460,000 |
| 3000 | 12,552,000 |
| 5000 | 20,920,000 |
About these units
Kilocalorie
The kilocalorie (food Calorie) was defined as the amount of heat needed to raise one kilogram of water by 1°C. It entered food science in the late 19th century when scientists first measured the energy content of food by combustion calorimetry.
Joule
The joule is the SI unit of energy, equivalent to one newton-meter. Its adoption by the scientific community means that nutritional energy is increasingly expressed in kilojoules (kJ) alongside kilocalories on food labels in many countries.
Frequently asked questions
One dietary Calorie (1 kcal) = 4184 joules.
The small calorie (cal) is 4.184 J; the kilocalorie (kcal or Calorie with capital C) is 4184 J. Food energy uses kilocalories, but packaging often writes "Cal" or "kcal" to mean the same thing.
2000 kcal × 4.184 kJ/kcal = 8368 kJ — a typical adult daily energy need.