Convert Kilocalories to BTU
Kilocalories to BTU is the conversion you need when a food or heat figure is in Calories but you want the British thermal unit used for heating, cooking, and HVAC ratings. One kilocalorie is approximately 3.965667 BTU, so the BTU number always comes out larger.
Kilocalories to British thermal units conversion table
| Kilocalories (kcal) | British thermal units (BTU) |
|---|---|
| 1 | 3.965667 |
| 2 | 7.931334 |
| 3 | 11.897 |
| 5 | 19.828334 |
| 10 | 39.656668 |
| 20 | 79.313337 |
| 50 | 198.283342 |
| 100 | 396.566683 |
| 500 | 1,982.833416 |
| 1,000 | 3,965.666831 |
The formula
To convert kilocalories to BTU, multiply the number of kilocalories by 3.9656668313909194 (about 3.965667):
BTU = kilocalories × 3.9656668313909194
A worked example
Say you have 100 kcal — 100 food Calories — and want it in BTU:
100 × 3.9656668313909194 = 396.56668 BTU
So 100 kilocalories is about 396.56668 BTU.
Why it's an approximation
A "kilocalorie" (kcal) is the "Calorie" you see on food nutrition labels — one food Calorie is one kilocalorie. The kilocalorie itself is exact (4184 joules), but the BTU here is the International Table BTU, which comes from a different definition. The two don't divide evenly, so the factor 3.965667 runs on past several decimal places and gets rounded for everyday use.
When you'll use it
Matching food or heat energy against the BTU ratings on stoves, furnaces, and air conditioners, comparing cooking and heating figures quoted in different units, and putting Calories and BTU onto the same scale.
Frequently asked questions
How many BTU are in a kilocalorie?
About 3.965667 BTU. It's a rounded figure — the exact value runs on past several decimal places, so 3.965667 is the practical number to use. This uses the International Table BTU.
Is a kilocalorie the same as a food Calorie?
Yes. The 'Calorie' with a capital C on a nutrition label is a kilocalorie — one food Calorie is one kilocalorie. So 100 food Calories is about 396.56668 BTU.
Is the kilocalories to BTU conversion exact?
No. The kilocalorie and the International Table BTU come from different definitions and don't divide evenly, so the factor 3.965667 is rounded for everyday use. More decimal places give you more precision if you need it.