The British thermal unit (BTU) is the energy needed to raise one pound of water by one degree Fahrenheit, widely used for heating and air-conditioning ratings.
Btu to Calories
Convert British thermal unit (BTU) to Calorie (cal) instantly with an exact formula, conversion table, and FAQ.
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Convert btu (BTU) to calories (cal) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C.
cal = BTU × 252.1644007
Results update instantly for Btu to Calories conversions.
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Formula
cal = BTU × 252.1644007
BTU = cal × 0.003965666831
Conversion table
| 1 BTU | 252.164401 cal |
| 5 BTU | 1260.822004 cal |
| 10 BTU | 2521.644007 cal |
| 20 BTU | 5043.288014 cal |
| 50 BTU | 12608.220036 cal |
| 100 BTU | 25216.440072 cal |
| 500 BTU | 126082.200361 cal |
| 1000 BTU | 252164.400722 cal |
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How the formula works
Both british thermal unit and calorie measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in btu by 252.1644007 to get calories. To reverse the conversion, multiply a calorie value by 0.003965666831 to get back to btu.
Frequently asked questions
What is British thermal unit (BTU)?
The British thermal unit (BTU) is the energy needed to raise one pound of water by one degree Fahrenheit, widely used for heating and air-conditioning ratings.
What is Calorie (cal)?
A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C.
How do I convert btu to calories?
Multiply the british thermal unit value by 252.1644007 to get the equivalent in calories. For example, 5 BTU × 252.1644007 = 1260.822004 cal.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 252.1644007 is an exact, non-rounded value.
Can I convert calories back to btu?
Yes. Divide the calorie value by 252.1644007, or multiply it by 0.003965666831, to get btu.
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About converting btu to calories
The British thermal unit (BTU) is the energy needed to raise one pound of water by one degree Fahrenheit, widely used for heating and air-conditioning ratings. A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C.
Use this calculator to move between btu and calories accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.