Joules to BTU – convert J to British thermal units
Convert joules to BTU (J to British thermal units) to compare scientific energy figures with the BTU ratings commonly used for boilers, radiators, air conditioners and heaters.
Open the interactive J → BTU converter:
Use main converter (J → BTU) or switch to BTU → JThe energy converter also supports kJ, MJ and kWh so you can link BTU with SI units and utility bills.
Quick reference: joules to BTU
One BTU is about 1055.06 J, so: BTU = J ÷ 1055.06. Examples:
| Energy (J) | Energy (BTU, approx.) |
|---|---|
| 1,000 J | 0.95 BTU |
| 5,000 J | 4.74 BTU |
| 10,000 J | 9.48 BTU |
| 50,000 J | 47.39 BTU |
| 100,000 J | 94.78 BTU |
| 1,000,000 J | 947.8 BTU |
Why convert joules to BTU?
J to BTU is useful when you:
- Compare fuel energy content (in J or kJ) with appliance BTU ratings.
- Size heating and cooling equipment for rooms or buildings.
- Translate physics or thermodynamics calculations into HVAC terms.
- Relate boiler or heat pump outputs to insulation and heat loss data.
Other energy converters on this site
Rounding to two decimal places is usually fine for practical heating estimates, but the main converter keeps full precision.
Page last updated: 4 December 2025.