BTU to Watts Converter (BTU/h)
Updated Formulas shown
Divide BTU per hour by 3.41214 to get watts: a 12,000 BTU/h air conditioner (one "ton") moves 3,517 W of heat. That is its cooling output, not the electricity it uses.
Formula: watts = BTU per hour ÷ 3.4121416331 (exact ratio, shown rounded)
Common values: BTU per hour → watts
| BTU per hour | watts |
|---|---|
| 0.293071 W | |
| 0.586142 W | |
| 0.879213 W | |
| 1.46536 W | |
| 2.93071 W | |
| 5.86142 W | |
| 7.32678 W | |
| 14.6536 W | |
| 29.3071 W | |
| 73.2678 W | |
| 146.536 W | |
| 293.071 W |
12,000 BTU/h in every power unit
- 3,516.85 W
- 3.51685 kW
- 0.00351685 MW
- 4.71618 hp
- 4.78159 PS
- 1 ton (AC)
- 3,025.97 kcal/h
How to convert BTU per hour to watts
- Type the value in BTU per hour into the converter (or into the right-hand box to go the other way).
- Divide by 3.4121416331 to get watts.
- Round to a sensible precision with the Decimals control; the table below covers the values people look up most.
- To estimate the electricity an AC draws, divide its BTU/h by its EER: 12,000 ÷ 12 = 1,000 W.
BTU per hour to watt formula
watts = BTU per hour ÷ 3.4121416331 — 1 BTU/h = 0.29307107 W. Both units are defined exactly (NIST SP 811); the factor above is rounded to 10 decimals, and the converter uses the full-precision ratio.
BTU/h to W conversion table
Air conditioner and mini-split sizes
| BTU/h | watts | kW | tons |
|---|---|---|---|
| 5,000 | 1,465 | 1.47 | 0.42 |
| 6,000 | 1,758 | 1.76 | 0.5 |
| 8,000 | 2,345 | 2.34 | 0.67 |
| 9,000 | 2,638 | 2.64 | 0.75 |
| 10,000 | 2,931 | 2.93 | 0.83 |
| 12,000 | 3,517 | 3.52 | 1 |
| 15,000 | 4,396 | 4.4 | 1.25 |
| 18,000 | 5,275 | 5.28 | 1.5 |
| 24,000 | 7,034 | 7.03 | 2 |
| 30,000 | 8,792 | 8.79 | 2.5 |
| 36,000 | 10,551 | 10.55 | 3 |
| 42,000 | 12,309 | 12.31 | 3.5 |
| 48,000 | 14,067 | 14.07 | 4 |
| 60,000 | 17,584 | 17.58 | 5 |
Output vs input power
AC and heat pump BTU ratings are heat moved per hour. The electrical draw is much lower because a heat pump moves heat rather than making it: EER = BTU/h ÷ input watts, so a 12,000 BTU/h window unit with an EER of 12 draws about 1,000 W. Electric resistance heaters are the exception — every watt becomes heat, so a 1,500 W space heater gives 5,118 BTU/h. Size a unit for the room with the BTU calculator.
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Frequently asked questions
How many watts is 12,000 BTU?
12,000 BTU/h = 3,517 W of cooling. A typical unit draws 1,000–1,200 W of electricity to deliver it.
How many watts is 5,000 BTU?
1,465 W of cooling output; a 5,000 BTU window unit draws about 400–500 W.
Is BTU the same as BTU/h?
No. BTU is energy; BTU/h is a rate (power). AC and furnace sizes are BTU/h even when the label just says "BTU".
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Estimates only. Check quantities with your supplier or contractor before ordering.