How to convert calories to BTU
To convert calories to BTU, multiply the value by the conversion factor 0.0039656668. To go the other way, multiply by 252.1644007 (or divide by 0.0039656668).
Worked example: 25 cal to BTU
- Write the value: 25 cal
- Multiply by 0.0039656668: 25 × 0.0039656668
- Result: 0.0991417 BTU
Calorie to BTU conversion table
Quick reference values, rounded to 6 significant digits.
| Calorie (cal) | BTU (BTU) |
|---|---|
| 0.1 cal | 0.000396567 BTU |
| 0.25 cal | 0.000991417 BTU |
| 0.5 cal | 0.00198283 BTU |
| 1 cal | 0.00396567 BTU |
| 2 cal | 0.00793133 BTU |
| 3 cal | 0.011897 BTU |
| 4 cal | 0.0158627 BTU |
| 5 cal | 0.0198283 BTU |
| 6 cal | 0.023794 BTU |
| 7 cal | 0.0277597 BTU |
| 8 cal | 0.0317253 BTU |
| 9 cal | 0.035691 BTU |
| 10 cal | 0.0396567 BTU |
| 12 cal | 0.047588 BTU |
| 15 cal | 0.059485 BTU |
| 20 cal | 0.0793133 BTU |
| 25 cal | 0.0991417 BTU |
| 30 cal | 0.11897 BTU |
| 40 cal | 0.158627 BTU |
| 50 cal | 0.198283 BTU |
| 75 cal | 0.297425 BTU |
| 100 cal | 0.396567 BTU |
| 250 cal | 0.991417 BTU |
| 500 cal | 1.98283 BTU |
| 1,000 cal | 3.96567 BTU |
BTU to Calorie
| BTU | cal |
|---|---|
| 1 BTU | 252.164 cal |
| 5 BTU | 1,260.82 cal |
| 10 BTU | 2,521.64 cal |
| 50 BTU | 12,608.22 cal |
| 100 BTU | 25,216.44 cal |
1 Calorie in other energy units
About Calorie and BTU
What is a calorie (cal)?
A small calorie is the energy to raise 1 g of water by 1 °C (4.184 J).
What is a btu (BTU)?
A British Thermal Unit is the energy to heat one pound of water by 1 °F.
Where calorie to btu conversion is used
Energy conversions are needed for electricity bills, food calories, heating, batteries and physics. Converting between calories and BTU is especially common when you compare products, read foreign specifications, or fill in forms that expect a specific unit.
Need every unit at once? Use the full Energy Converter.
Frequently asked questions
How many BTU are in 1 calorie?
1 Calorie equals 0.00396567 BTU.
How do I convert calories to BTU?
Multiply the number of calories by 0.0039656668. For example, 25 cal × 0.0039656668 = 0.0991417 BTU.
What is 25 cal in BTU?
25 cal = 0.0991417 BTU.
How many calories are in 1 btu?
1 BTU equals 252.164 cal. Use the BTU to Calories converter for the reverse direction.
Is this Calorie to BTU converter accurate?
Yes. It uses exact internationally defined conversion factors, calculated with full floating-point precision. Results are displayed rounded for readability.