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Energy
BTU to Joules
Convert BTU (BTU) to joules (J). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 BTU = 1055.06 J
BTU to Joules Conversion Table
Common values, ready to copy:
| BTU | joules |
|---|---|
| 1 BTU | 1055.06 J |
| 2 BTU | 2110.12 J |
| 5 BTU | 5275.3 J |
| 10 BTU | 10550.6 J |
| 25 BTU | 26376.5 J |
| 50 BTU | 52753 J |
| 100 BTU | 105506 J |
| 1,000 BTU | 1.0551e+6 J |
Formula
joules = BTU × 1055.06
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
About BTU and Joules
BTU (BTU): British Thermal Unit; the energy to raise one pound of water by one degree Fahrenheit; defined as exactly 1,055.06 J. Common uses: US heating and air conditioning (a 24,000 BTU air conditioner cools roughly a 1,500 sq ft room), and US natural gas billing.
Joules (J): The SI unit of energy; named for James Prescott Joule, whose 19th-century experiments established the equivalence of mechanical work and heat. Common uses: Physics calculations, food calorie labeling in metric countries (kilojoules), battery capacity, and chemistry.
How the conversion works
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
The exact relationship is joules = BTU × 1055.06, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between BTU and joules comes up wherever energy measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.