BTU to Kilojoules Converter
BTU → kJ · ⚡ Energy
1 BTU = 1.05506 Kilojoules
How to convert BTU to Kilojoules
To convert BTU to Kilojoules, multiply the value in BTU by 1.05506. For example, 5 BTU = 5.2753 kJ.
Converting BTU (BTU) to Kilojoules (kJ) is a frequent need, and the exact relationship is 1 BTU = 1.05506 kJ. Whether you're working on a project, checking a specification, or just curious, the calculator above gives you the answer instantly for any value you enter.
Energy conversions appear in nutrition, fitness, physics, utility bills, and engineering. The same quantity of energy can be expressed in joules, calories, kilowatt-hours, or BTU depending on the context.
Understanding BTU and Kilojoules
The joule is the SI unit, but everyday contexts use others: food labels use kilocalories (often just called 'calories'), electricity bills use kilowatt-hours, and heating and cooling systems use BTU (British Thermal Units). One food calorie is actually a kilocalorie — 1,000 of the small physics calories — which is a frequent source of confusion.
How accurate is this conversion?
Energy conversions use standard definitions: 1 calorie = 4.184 joules, 1 kilowatt-hour = 3,600,000 joules, 1 BTU = 1,055.06 joules. These are internationally agreed values, making the conversions exact.
All conversion factors on ClearUnits are based on internationally recognised standards (the International System of Units, SI, and official definitions). Factors are reviewed for accuracy and the calculator uses full-precision values, rounding only the displayed result.
Quick reference: common BTU to Kilojoules values
The most frequently searched conversions are 1 BTU = 1.05506 Kilojoules, 5 BTU = 5.2753 Kilojoules, 10 BTU = 10.5506 Kilojoules, and 100 BTU = 105.506 Kilojoules. The full table further down covers every common value, and the calculator handles any number you need in between.
Pro tip: When comparing appliance efficiency or heating costs, convert everything to kilowatt-hours first, since that's the unit your utility bill uses — it makes the real-world cost immediately comparable.
BTU to Kilojoules — Conversion Table
| BTU (BTU) | Kilojoules (kJ) |
|---|---|
| 0.1 BTU | 0.105506 kJ |
| 0.25 BTU | 0.263765 kJ |
| 0.5 BTU | 0.52753 kJ |
| 1 BTU | 1.05506 kJ |
| 2 BTU | 2.11012 kJ |
| 5 BTU | 5.2753 kJ |
| 10 BTU | 10.5506 kJ |
| 25 BTU | 26.3765 kJ |
| 50 BTU | 52.753 kJ |
| 100 BTU | 105.506 kJ |
| 250 BTU | 263.765 kJ |
| 500 BTU | 527.53 kJ |
| 1000 BTU | 1,055.06 kJ |