Convert BTU to Kilocalories
BTU to kilocalories is the conversion you need when a heat rating is in British thermal units but you think in the kilocalories used for food energy and heating. One BTU is approximately 0.252164 kilocalories, so the kilocalorie number always comes out about a quarter of the BTU figure.
British thermal units to Kilocalories conversion table
| British thermal units (BTU) | Kilocalories (kcal) |
|---|---|
| 1 | 0.252164 |
| 2 | 0.504329 |
| 3 | 0.756493 |
| 5 | 1.260822 |
| 10 | 2.521644 |
| 20 | 5.043288 |
| 50 | 12.60822 |
| 100 | 25.21644 |
| 500 | 126.0822 |
| 1,000 | 252.164401 |
The formula
To convert BTU to kilocalories, multiply the number of BTU by 0.252164 (about 0.2521644007217973):
kilocalories = BTU × 0.252164
A worked example
Say you have 1000 BTU and want it in kilocalories:
1000 × 0.2521644007217973 = 252.1644 kcal
So 1000 BTU is about 252 kilocalories — that is, about 252 food Calories.
Why it's an approximation
The BTU and the kilocalorie are both heat units, but they're defined from different starting points — one from warming a pound of water by a degree Fahrenheit, the other from warming a kilogram of water by a degree Celsius. Those definitions don't divide evenly into each other, so the factor 0.2521644007217973 doesn't stop at a clean value. Rounded to 0.252164 it's plenty accurate for everyday use, and it stays approximate no matter how many decimals you keep.
When you'll use it
Comparing a heater or stove's BTU output against the kilocalories (food Calories) you're more used to, checking heating figures in regions that rate energy in kilocalories, or working a problem where the other numbers are already in kilocalories.
Frequently asked questions
How many kilocalories are in a BTU?
Approximately 0.252164 kilocalories. It's a rounded figure — the exact value runs on well past those decimal places, so 0.252164 is the practical number to use.
Is a kilocalorie the same as a food Calorie?
Yes. The kilocalorie (kcal) is the food-label 'Calorie' with a capital C. So a BTU works out to roughly a quarter of one food Calorie.
Is the BTU to kilocalories conversion exact?
No. The BTU and the kilocalorie don't divide evenly, so the factor 0.252164 is rounded for everyday use. More decimal places give you more precision if you need it.