US therm used for natural gas energy.
US therms to Calories Converter — therm to cal
Convert US therm (therm) to Calorie (cal) using the exact conversion factor (1 us therm = 25,210,420.65 calorie). See the formula, worked examples, conversion table, history, and common uses.
US therms to Calories converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
A thermochemical calorie is 4.184 joules.
Result = input x 1.054804e+8 / 4.184.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting US therms to Calories
US therm and Calorie both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Specifically: US therm used for natural gas energy, and a thermochemical calorie is 4.184 joules.
Formula
calories = us therms × 25210420.6501
This factor comes from each unit's defined relationship to the category's base unit: 1 us therm equals 105480400 base units, and 1 calorie equals 4.184 base units, so dividing one by the other gives the direct us therm-to-calorie factor of 25210420.6501.
Simple example
1 therm × 25210420.65 = 25,210,420.65 cal
1 us therm = 25,210,420.65 calories.
Real-world example
100 therm × 25210420.65 = 2,521,042,065 cal
100 us therms = 2,521,042,065 calories.
Conversion table
| US therm (therm) | Calorie (cal) |
|---|---|
| 1 therm | 25,210,420.65 cal |
| 10 therm | 252,104,206.5 cal |
| 50 therm | 1,260,521,033 cal |
| 100 therm | 2,521,042,065 cal |
| 500 therm | 12,605,210,330 cal |
| 1,000 therm | 25,210,420,650 cal |
Reverse conversion: Calorie to US therm
1 cal × 3.966614e-8 = 3.966614e-8 therm
1 calorie = 3.966614e-8 us therms.
us therms = calories × 3.966614e-8
For a page dedicated to this direction, see Calorie to US therm.
Understanding the US therm (therm)
US therm used for natural gas energy.
Understanding the Calorie
Calorie (cal) measures energy. The thermochemical calorie used in this converter is defined as exactly 4.184 joules. It is classified as a Non-SI unit (limited use with SI).
Where it's used: Nutrition labeling in the US and several other countries still commonly uses the kilocalorie (as 'Calorie')
Calorie vs. Calorie (kilocalorie). Food labels' capitalized 'Calorie' is actually one kilocalorie (1,000 small calories) — a long-standing labeling convention that causes frequent confusion.
Uses of the Calorie today
- Food energy labeling (as kilocalories, often written 'Calories')
- Historical chemistry and thermodynamics contexts
History of the Calorie
The calorie was originally defined in the early 19th century as the heat needed to raise one gram of water by one degree Celsius, but different scientific traditions defined it at slightly different reference temperatures, producing several close but non-identical 'calorie' values historically (15 °C calorie, mean calorie, thermochemical calorie).
To resolve this ambiguity, the thermochemical calorie was fixed by convention at exactly 4.184 joules; the very similar International Table calorie is fixed at exactly 4.1868 joules. The nutritional 'Calorie' seen on food labels is actually a kilocalorie (1,000 calories).
Historical origin. Calorie was not the invention of a single named person; it developed through the process described above.
Calorie — sources
- NIST Special Publication 811 — Documents the thermochemical calorie's exact joule equivalence.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many calories are in 1 us therm?
1 us therm equals 25,210,420.65 calories, using the exact defined conversion factor rather than an estimate.
How do I convert us therm to calorie?
Multiply the us therm value by 25210420.65. The converter above does this instantly to whatever precision you set.
How do I convert calorie back to us therm?
Use the reverse factor: 1 calorie equals 3.966614e-8 us therms. You can also use the swap control in the converter above to flip the direction instantly.
What is a us therm?
US therm (therm) is a unit of engineering.
What is a calorie?
Calorie (cal) measures energy. The thermochemical calorie used in this converter is defined as exactly 4.184 joules. It is classified as a Non-SI unit (limited use with SI).
Is the us therm to calorie conversion exact?
Yes. The thermochemical calorie used in this converter is defined as exactly 4.184 joules. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between calorie vs. calorie (kilocalorie)?
Food labels' capitalized 'Calorie' is actually one kilocalorie (1,000 small calories) — a long-standing labeling convention that causes frequent confusion.