Direct conversion
Convert calorie [cal] to British thermal unit [BTU] instantly with formula, examples, chart, and FAQs.
Quick answer
Use the calculator below for any custom value, then check the formula, examples, chart, and reverse conversion links.
1 calorie [cal] = 0.003966 British thermal unit [BTU]
1 calorie [cal] = 0.003966 British thermal unit [BTU]
Example: 1 calorie [cal] equals 0.003966 British thermal unit [BTU].
Energy conversions use joule as the reference unit, including electrical, thermal, nutrition, and mechanical energy units.
Displayed results are rounded for readability. The calculator keeps enough precision for everyday use and switches to scientific notation for very large or very small values. Last reviewed: 2026-05-21.
The calorie is an energy unit traditionally based on heating water by one degree Celsius.
HistoryCalories were used in heat measurement before joules became the SI standard.
Current useCalories are used in nutrition, food labels, exercise estimates, and diet planning.
The British thermal unit (BTU) is a energy unit used to express measurements in this converter.
HistoryThis unit is included because it appears in practical measurement systems, technical references, product specifications, or everyday conversion needs.
Current useUse British thermal unit when comparing energy values, checking specifications, converting between systems, or preparing quick estimates.
| calorie [cal] | British thermal unit [BTU] |
|---|---|
| 1 | 0.003966 |
| 2 | 0.007931 |
| 5 | 0.019828 |
| 10 | 0.039657 |
| 20 | 0.079313 |
| 25 | 0.099142 |
| 50 | 0.198283 |
| 100 | 0.396567 |
| 1000 | 3.965667 |
Use this formula: 1 calorie [cal] = 0.003966 British thermal unit [BTU] Enter your value in the calculator and the result updates instantly.
1 calorie [cal] equals 0.003966 British thermal unit [BTU].
Yes. Use the swap button in the calculator or open the related reverse conversion link when it is listed on this page.