Calorie to British Thermal Unit Converter
Energy · unit-converter
Convert Calorie to British Thermal Unit with fixed input and output units, a step-by-step formula line, and reference tables. Factors are joule-based; food energy uses thermochemical calories. The full Energy Converter also includes MMBtu, toe, thermal kWh, and MeV/GeV.
Calculator
From: Calorie (cal)
To: British Thermal Unit (btu)
About Calorie
The small calorie (cal) is 4.184 J in this converter (thermochemical). Do not confuse with the dietary kilocalorie (kcal).
About British Thermal Unit
The British thermal unit used here is the IT BTU: ≈ 1,055.056 J. It appears in HVAC, heating equipment, and US engineering data.
How to convert calories to british thermal units
1 calorie is equal to 0.00396566683139 british thermal unit when both are expressed in joule-equivalents:
1 cal = (4.184 J ÷ 1,055.05585262 J) btu = 0.00396566683139 btu
Each calorie is defined as 4.184 J and each british thermal unit as 1,055.05585262 J in this tool, so one cal equals 4.184 ÷ 1,055.05585262 btu = 0.00396566683139 btu.
Let d(cal) be the numeric amount in Calorie (cal), and d(btu) the amount in British Thermal Unit (btu). Then:
d(btu) = d(cal) × (4.184 / 1,055.05585262)
Equivalently, divide by how many cal fit into one btu (joules per btu divided by joules per cal):
d(btu) = d(cal) ÷ 252.16440072179731
Or: british thermal unit = calorie ÷ 252.16440072179731
Examples
Example #1: Convert 1 cal to british thermal unit
1 cal = 1 cal × (4.184/1,055.05585262) btu = 0.0039656668 btu
1 cal = 1 cal ÷ 252.16440072179731 = 0.0039656668 btu
Example #2: Convert 10 cal to british thermal unit
10 cal = 10 cal × (4.184/1,055.05585262) btu = 0.0396566683 btu
10 cal = 10 cal ÷ 252.16440072179731 = 0.0396566683 btu
Summary
To convert Calorie to British Thermal Unit, multiply the value in cal by the ratio of joules per cal divided by joules per btu. Equivalently: value_btu = value_cal × (4.184 / 1055.05585262). Numerically, 1 cal equals 0.003965666831390919 btu.
Relationship context
You are converting between food / nutrition energy (calories) (Calories) and US / imperial engineering units (BTU, therm, ft·lb) (British Thermal Units). All values are mapped through joules first. The numeric factor is 3.965667e-3.
Conversion tables
| Calorie (cal) | British Thermal Unit (btu) |
|---|---|
| 0.1 | 0.0003965667 |
| 1 | 0.0039656668 |
| 2 | 0.0079313337 |
| 3 | 0.0118970005 |
| 4 | 0.0158626673 |
| 5 | 0.0198283342 |
| 6 | 0.023794001 |
| 7 | 0.0277596678 |
| 8 | 0.0317253347 |
| 9 | 0.0356910015 |
| Calorie (cal) | British Thermal Unit (btu) |
|---|---|
| 10 | 0.0396566683 |
| 20 | 0.0793133366 |
| 30 | 0.1189700049 |
| 40 | 0.1586266733 |
| 50 | 0.1982833416 |
| 60 | 0.2379400099 |
| 70 | 0.2775966782 |
| 80 | 0.3172533465 |
| 90 | 0.3569100148 |
| 100 | 0.3965666831 |