BTU to kW converter
BTU to kW for air conditioners and heaters: 1 kW = 3,412.14 BTU per hour, so a 12,000 BTU unit has 3.5169 kW. Type a rating and the kilowatts appear as you type, with watts and tons of refrigeration below; kW to BTU works in the same box.
Example: Power 12,000 · Direction: BTU/h to kW → Answer: 12,000 BTU/h = 3.5169 kW. Source: NIST Special Publication 811, Appendix B.8 and footnote 9: Btu_IT = 1.055 055 852 62 E+03 J (exact), Btu_IT/h = 2.930 711 E−01 W, ton of refrigeration = 12 000 Btu_IT/h = 3.516 853 E+03 W (read 15.10.2026). Updated: .
How it is calculated
How to convert BTU to kW
kW = BTU/h × 0.00029307, or kW = BTU/h ÷ 3,412.14. The international table BTU is exactly 1,055.05585262 joules. Spread over one hour (3,600 s) that is 0.29307 W, so 12,000 BTU/h = 3,516.9 W = 3.5169 kW. Backwards, BTU/h = kW × 3,412.14: a 2.5 kW split unit delivers 8,530 BTU/h.
BTU to kW chart
| BTU/h | kW |
|---|---|
| 5,000 | 1.4654 |
| 9,000 | 2.6376 |
| 12,000 | 3.5169 |
| 18,000 | 5.2753 |
| 24,000 | 7.0337 |
BTU, BTU/h and kWh
Air conditioner labels say "12,000 BTU" but mean BTU per hour, a power like kW. The same factor works for energy: 1 kWh = 3,412.14 BTU. A "ton" of cooling is 12,000 BTU/h, the heat needed to melt one short ton of ice in a day, which is 3.5169 kW. The kW figure on a European unit is the cooling output, not the electricity it draws; that is usually a third or less.
To size a unit for a room, use the BTU calculator. Other energy units such as calories or joules are in the energy converter, and engine power in hp to kW.
Frequently asked questions
How many kW is 12,000 BTU?
12,000 BTU/h = 3.5169 kW, also called one ton of cooling.
How do I convert BTU to kW?
Multiply BTU/h by 0.00029307, or divide by 3,412.14: 9,000 BTU/h = 2.6376 kW.
How many BTU is 1 kW?
1 kW = 3,412.14 BTU/h.
How many kW is 24,000 BTU?
24,000 BTU/h = 7.0337 kW.
Is BTU to kW the same as BTU to kWh?
The factor is the same, 3,412.14, but BTU/h and kW are power, while BTU and kWh are energy.
Sources and legal basis
As of: · Editorial policy
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