How to Convert Watts to BTU per hour (W to BTU/h)
Power conversions help compare car engines in hp and kW, and air-con units rated in BTU/h against their electrical draw in watts. This guide shows how to convert watts into btu per hour by hand, with examples and a quick-reference table.
The conversion
To convert watts to btu per hour, multiply the value by 3.4121416351. To go the other way, divide by the same number (or multiply by 0.29307107). For a quick estimate, multiply by about 3.4.
BTU per hour = watts × 3.4121416351
Worked examples
- 3 W = 10.2364 BTU/h
- 12.5 W = 42.6518 BTU/h
- 75 W = 255.9106 BTU/h
Watts to BTU per hour table
| Watts | BTU per hour |
|---|---|
| 1 W | 3.4121 BTU/h |
| 2 W | 6.8243 BTU/h |
| 5 W | 17.0607 BTU/h |
| 10 W | 34.1214 BTU/h |
| 20 W | 68.2428 BTU/h |
| 25 W | 85.3035 BTU/h |
| 50 W | 170.6071 BTU/h |
| 100 W | 341.2142 BTU/h |
| 250 W | 853.0354 BTU/h |
| 500 W | 1,706.07 BTU/h |
| 1,000 W | 3,412.14 BTU/h |
Common questions
Is W to BTU/h exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the BTU per hour to Watts converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Background
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For any value, use the Watts to BTU per hour Converter or browse all power converters.
Run your own numbers: Watts to BTU per hour Converter