1 cal = 4.184 J
| Calorie (cal) | Joule (J) |
|---|---|
| 1 | 4.184 |
| 5 | 20.92 |
| 10 | 41.84 |
| 25 | 104.6 |
| 50 | 209.2 |
| 100 | 418.4 |
| 200 | 836.8 |
| 250 | 1046 |
| 500 | 2092 |
| 750 | 3138 |
| 1000 | 4184 |
| 1500 | 6276 |
| 2000 | 8368 |
| 2500 | 10460 |
| 5000 | 20920 |
| 10000 | 41840 |
| 50000 | 209200 |
| 100000 | 418400 |
| 500000 | 2092000 |
| 1000000 | 4184000 |
To convert calories (thermochemical) to joules, multiply by 4.184. Note: the food "Calorie" (uppercase C, or kilocalorie) = 1,000 small calories = 4,184 joules.
1 cal = 4.184 J
Convert 250 small calories to joules: 250 × 4.184 = 1,046 J
Convert 2,000 food Calories (kcal) to joules: 2,000 × 4,184 = 8,368,000 J (8,368 kJ)
To convert joules to calories, divide by 4.184.
\u2022 1 calorie (4.184 J) is the energy needed to heat 1 gram of water by 1°C.
\u2022 1 food Calorie (4,184 J) is 1,000 small calories — what you see on nutrition labels.
\u2022 2,000 food Calories (8.37 MJ) is the average daily energy intake for an adult.
\u2022 A 100-watt lightbulb uses 100 joules per second.
Calories and joules both measure energy but in different contexts. The calorie originated in heat measurement, while the joule is the SI standard for all forms of energy. Understanding the relationship is important for nutrition science, physics, and chemistry.
There’s a common confusion: the "calorie" on food labels is actually a kilocalorie (kcal), sometimes written with a capital C as "Calorie." One food Calorie = 1 kcal = 1,000 small calories = 4,184 joules. This converter uses small (thermochemical) calories. For food Calories, multiply the result by 1,000.
In science, the joule has largely replaced the calorie as the standard energy unit. Chemical reaction energies, heat capacities, and thermodynamic calculations all use joules. However, the calorie persists in some chemistry contexts (calorie per gram, calorie per mole).
Nutrition labels worldwide are shifting toward kilojoules. A 2,000 kcal daily diet is about 8,368 kJ. A banana has about 105 kcal (440 kJ). Running burns about 400-600 kcal (1,674-2,510 kJ) per hour. Many countries now require both kcal and kJ on food labels.
One small (thermochemical) calorie equals 4.184 joules. One food Calorie (kilocalorie) equals 4,184 joules.
A small calorie (cal) is the energy to heat 1g of water by 1°C. A food Calorie (Cal or kcal) is 1,000 small calories. Nutrition labels use kilocalories.
1 food Calorie (kcal) = 4.184 kilojoules (kJ).
The joule is the SI standard energy unit and works consistently across all energy types (thermal, electrical, mechanical). The calorie is specific to heat and water.