Kilocalories to British Thermal Units Converter
1 kilocalorie ≈ 3.96566683 British thermal units
This is the unit written as "Calories" on nutrition labels.
Several BTU definitions exist. This converter uses the International Table BTU, the one used by HVAC equipment ratings.
1 kilocalorie equals 3.96567 British thermal units
How to convert kilocalories to British thermal units
Calories here are thermochemical (4.184 J), while BTU uses the International Table definition. A kilowatt-hour is energy (3.6 MJ), not power; a food Calorie is a kilocalorie.
BTU = kcal × 3.965666831One kilocalorie is 3.965666831 British thermal units, so a single multiplication converts any value.
39.6567 BTU ≈ 10 × 3.965666831This is the unit written as "Calories" on nutrition labels.
Several BTU definitions exist. This converter uses the International Table BTU, the one used by HVAC equipment ratings.
Kilocalories to British thermal units conversion table
Common values in kilocalories, converted to British thermal units.
| Kilocalories (kcal) | British thermal units (BTU) |
|---|---|
| 1 | 3.9656668 |
| 2 | 7.9313337 |
| 3 | 11.897 |
| 4 | 15.862667 |
| 5 | 19.828334 |
| 10 | 39.656668 |
| 20 | 79.313337 |
| 25 | 99.141671 |
| 50 | 198.28334 |
| 100 | 396.56668 |
| 250 | 991.41671 |
| 500 | 1,982.8334 |
| 1,000 | 3,965.6668 |
About these units
kilocaloriekcal
One thousand thermochemical calories: exactly 4,184 joules.
British thermal unitBTU
The International Table BTU: 1,055.05585262 joules. The US heating and cooling unit.
Reference: NIST Special Publication 811.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.