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.
Calories to Therms
Convert Calorie (cal) to US therm (therm) instantly with an exact formula, conversion table, and FAQ.
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Convert calories (cal) to therms (therm) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
The US therm is a natural-gas billing unit equal to 100,000 BTU, used by utilities to measure gas usage.
therm = cal × 3.966613703e-08
Results update instantly for Calories to Therms conversions.
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Formula
therm = cal × 3.966613703e-08
cal = therm × 25210420.65
Conversion table
| 1 cal | 3.966614e-08 therm |
| 5 cal | 1.983307e-07 therm |
| 10 cal | 3.966614e-07 therm |
| 20 cal | 7.933227e-07 therm |
| 50 cal | 0.000002 therm |
| 100 cal | 0.000004 therm |
| 500 cal | 0.000020 therm |
| 1000 cal | 0.000040 therm |
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How the formula works
Both calorie and us therm measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in calories by 3.966613703e-08 to get therms. To reverse the conversion, multiply a us therm value by 25210420.65 to get back to calories.
Frequently asked questions
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.
What is US therm (therm)?
The US therm is a natural-gas billing unit equal to 100,000 BTU, used by utilities to measure gas usage.
How do I convert calories to therms?
Multiply the calorie value by 3.966613703e-08 to get the equivalent in therms. For example, 5 cal × 3.966613703e-08 = 1.983307e-07 therm.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 3.966613703e-08 is an exact, non-rounded value.
Can I convert therms back to calories?
Yes. Divide the us therm value by 3.966613703e-08, or multiply it by 25210420.65, to get calories.
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About converting calories to therms
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. The US therm is a natural-gas billing unit equal to 100,000 BTU, used by utilities to measure gas usage.
Use this calculator to move between calories and therms accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.