Calorie (th) to BTU (th) Converter
Convert Calorie (th) (cal) to BTU (th) (BTU) instantly. 1 cal = 0.003968 BTU.
Energy Converter
27 units available
1 cal = 0.003968 BTU
Formula:
BTU = cal × 0.0039683217With your value: 1 cal = 0.00396832 BTU
How big is that?
Everyday references on a logarithmic scale, all expressed in calorie (th) so you can sanity-check the result.
Other Calorie (th) to BTU (th) conversions
Calorie (th) to BTU (th) Conversion Table
| Calorie (th) (cal) | BTU (th) (BTU) |
|---|---|
| 0.5 | 0.001984 |
| 1 | 0.003968 |
| 2 | 0.007937 |
| 5 | 0.019842 |
| 10 | 0.039683 |
| 15 | 0.059525 |
| 20 | 0.079366 |
| 25 | 0.099208 |
| 50 | 0.198416 |
| 100 | 0.396832 |
| 250 | 0.99208 |
| 500 | 1.984161 |
| 1000 | 3.968322 |
BTU (th) to Calorie (th) Conversion Table
| BTU (th) (BTU) | Calorie (th) (cal) |
|---|---|
| 0.5 | 125.997849 |
| 1 | 251.995698 |
| 2 | 503.991396 |
| 5 | 1,259.978489 |
| 10 | 2,519.956979 |
| 15 | 3,779.935468 |
| 20 | 5,039.913958 |
| 25 | 6,299.892447 |
| 50 | 12,599.784895 |
| 100 | 25,199.56979 |
| 250 | 62,998.924474 |
| 500 | 125,997.848948 |
| 1000 | 251,995.697897 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Calorie (th) (cal)
Energy
The thermochemical calorie is exactly 4.184 J.
The International Table calorie (4.1868 J) and the 15 °C calorie differ slightly.
Source: NIST Special Publication 811, Guide for the Use of the International System of Units
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
BTU (th) (BTU)
Energy
The International Table BTU is exactly 1055.055 852 62 J.
Thermochemical and 39 °F BTU definitions differ by up to 0.2 %.
Source: NIST Special Publication 811, Guide for the Use of the International System of Units
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
How to Convert Calorie (th) to BTU (th)
To convert from Calorie (th) (cal) to BTU (th) (BTU), multiply the value by 0.0039683217.
Formula: BTU = cal × 0.0039683217
Reverse: cal = BTU × 251.9956978967
Step-by-Step Example
- Start with your value in Calorie (th). For example: 5 cal
- Multiply by the conversion factor: 5 x 0.0039683217
- The result is: 0.019842 BTU
About Calorie (th)
The thermochemical calorie equals 4.184 joules. Not to be confused with the food Calorie (kcal), which equals 1,000 calories.
Common uses: chemistry, nutrition, heating.
About BTU (th)
The btu (th) (BTU) is a unit of energy and work. One btu (th) equals 1054.35 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
Common uses: energy calculations, engineering and science, education.
Frequently Asked Questions
How many BTU (th) are in 1 Calorie (th)?
There are exactly 0.0039683217 BTU (th) in 1 Calorie (th). This means the conversion factor from Calorie (th) to BTU (th) is 0.0039683217.
What is the formula to convert Calorie (th) to BTU (th)?
The formula to convert Calorie (th) to BTU (th) is: BTU = cal × 0.0039683217. For example, to convert 10 Calorie (th) to BTU (th), you would multiply 10 by 0.0039683217.
What is a Calorie (th)?
The thermochemical calorie equals 4.184 joules. Not to be confused with the food Calorie (kcal), which equals 1,000 calories.
What is a BTU (th)?
The btu (th) (BTU) is a unit of energy and work. One btu (th) equals 1054.35 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
What are the common uses of Calorie (th)?
The Calorie (th) is commonly used in chemistry, nutrition, heating.
Related Energy Conversions
Cite this page
UnitConvertLab. (2026). Calorie (th) to BTU (th) converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/calorie-to-btu