Convert Btu to kilocalories or kilocalories to Btu with International Table and thermochemical unit options for energy conversions.
Assumptions Assumptions
- Conversions are energy-to-energy only; no power or rate conversions.
- Joules (J) are used as the base unit: values use standard constants shown below.
- Supported definitions: Btu (IT) = 1055.05585262 J; Btu (thermochemical) = 1054.35026444 J; kilocalorie (IT) = 4186.8 J; kilocalorie (thermochemical) = 4184 J.
- “Calorie” on food labels (Cal) equals 1 kilocalorie (kcal).
- Results are rounded to 6 decimal places for display.
When to Use This Calculator
- Converting heating/cooling energy between Btu and food/thermal kilocalories.
- Comparing appliance energy ratings or fuel heat content across unit systems.
- Standardizing engineering or nutrition notes without manual lookup tables.
Input Definitions
- Btu — select International Table (IT) or thermochemical definition.
- Kilocalories — select IT or thermochemical definition; 1 kcal = 1 Cal (food calorie).
- Conversions — IT: kcal = Btu × 0.252164401; Btu = kcal × 3.968320719. General: kcal = Btu × (J_per_Btu ÷ J_per_kcal).
Customize This Calculator
Build your own version. Describe what you want changed, added, or compared.
Btu to Kilocalories Formula
The following formulas convert between Btu and kilocalories using the International Table (IT) definitions; other definitions are noted below.
- Btu (International Table) = 1055.05585262 J
- Btu (thermochemical) = 1054.35026444 J
- Kilocalorie (IT) = 4186.8 J
- Kilocalorie (thermochemical) = 4184 J
How do you convert Btu to kilocalories? For IT units, multiply Btu by 0.252164401; for thermochemical, multiply Btu by (1054.35026444 ÷ 4184) ≈ 0.252164.
How do you convert kilocalories to Btu? For IT units, multiply kilocalories by 3.968320719; for thermochemical, multiply kilocalories by (4184 ÷ 1054.35026444) ≈ 3.968321.
Btu to Kilocalories Conversion Table
| Btu (IT) | Kilocalories (IT) |
|---|---|
| 0.5 | 0.126082 |
| 1 | 0.252164 |
| 2 | 0.504329 |
| 3 | 0.756493 |
| 5 | 1.260822 |
| 10 | 2.521644 |
| 15 | 3.782466 |
| 20 | 5.043288 |
| 25 | 6.304110 |
| 30 | 7.564932 |
| 40 | 10.086576 |
| 50 | 12.108220 |
| 75 | 18.162330 |
| 100 | 25.216440 |
| 150 | 37.824660 |
| 200 | 50.432880 |
| 250 | 63.041100 |
| 500 | 126.082201 |
| 1000 | 252.164401 |
| * IT definitions: 1 Btu = 0.252164 kcal; 1 kcal = 3.968321 Btu (rounded). | |
Example Problem
Convert 2,500 Btu (IT) to kilocalories (IT).
Use the IT formula: kcal = Btu × 0.252164401.
kcal = 2,500 × 0.252164401 = 630.411003 ≈ 630.411 kcal
