Watts and BTU per hour
The watt is the SI unit of power: one joule per second. Light bulbs, appliances, chargers and solar panels are rated in watts.
One BTU per hour is about 0.293 watts. Air conditioners, heaters and furnaces in the US are sized in BTU/h, often written just "BTU".
Worked example
Convert 1,000 W: 1,000 × 3.412141633 = 3,412.141633, so 1,000 watts is 3,412.141633 BTU per hour. Likewise 2,000 W = 6,824.283266 BTU/h.
Estimating in your head
Multiply by 3.4 for a quick figure; it is off by about 0.4%. For 1,000 W that gives 3,400 BTU/h, against 3,412.14 exactly.
Going the other way
To convert BTU per hour to watts, divide by 3.412141633 (or multiply by 0.293071070172). The swap button between the boxes opens that page.
How this works
BTU/h = W × 3.412141633
1 W = 1 W and 1 BTU/h = ≈ 0.2930710702 W, both by definition, so the factor is their ratio: 3.412141633 (rounded here; the page uses the full value). Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many BTU per hour are in a watt?
1 watt = 3.412141633 BTU per hour. The factor is exact by definition but has endless decimals, so it is shown rounded; the page uses the full value.
How do I convert watts to BTU per hour?
Multiply by 3.412141633. For example, 2,000 W × 3.412141633 = 6,824.283266 BTU/h.
What is 10,000 W in BTU per hour?
10,000 W = 34,121.41633 BTU/h. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST SP 811 Appendix B.8 — Factors for units listed alphabetically
- NIST SP 811 Appendix B.9 — Factors for units listed by kind of quantity
- Wikipedia — Horsepower
Reviewed Oct 17, 2026 · test vectors fixtures/units/power/watts-to-btu-per-hour/