The calorie-to-joule conversion is one of the most common energy conversions in physics and chemistry. One small calorie equals 4.184 joules exactly. This converter turns the gram-calorie (lowercase c) into joules — the SI unit of energy — and back again, instantly and in your browser. It is built for lab work, homework and textbook problems, not nutrition labels.
How it works
The tool multiplies by a single exact constant. To go from calories to joules it computes J = cal × 4.184; to reverse it, cal = J ÷ 4.184. The 4.184 figure is the definition of the thermochemical calorie, so the conversion is exact rather than approximate. Be careful not to confuse this small calorie with the food Calorie (capital C) on nutrition labels, which is a kilocalorie equal to 1,000 small calories, or 4,184 J.
Example
Convert 100 cal to joules:
100 × 4.184 = 418.4 J
| Calories (cal) | Joules (J) |
|---|---|
| 1 | 4.184 |
| 10 | 41.84 |
| 100 | 418.4 |
| 1,000 | 4,184 |
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