BTU to Watt Hours
Convert btu (BTU) to watt hours (Wh). Both measure work and power, and the conversion comes up in nutrition, electricity, fitness work.
The Formula
``
watt hours = btu × 0.293071070172
btu = watt hours × 3.41214163313
`
One BTU is 0.293071 watt hours, and one watt hour is 3.4121 btu.
Conversion Table
| BTU | Watt Hours |
|---|---|
| 1 BTU | 0.293071 Wh |
| 2 BTU | 0.586142 Wh |
| 5 BTU | 1.4654 Wh |
| 10 BTU | 2.9307 Wh |
| 25 BTU | 7.3268 Wh |
| 50 BTU | 14.6536 Wh |
| 100 BTU | 29.3071 Wh |
| 500 BTU | 146.5355 Wh |
| 1,000 BTU | 293.0711 Wh |
The Other Direction
| Watt Hours | BTU |
|---|---|
| 1 Wh | 3.4121 BTU |
| 2 Wh | 6.8243 BTU |
| 5 Wh | 17.0607 BTU |
| 10 Wh | 34.1214 BTU |
| 25 Wh | 85.3035 BTU |
| 50 Wh | 170.6071 BTU |
| 100 Wh | 341.2142 BTU |
| 500 Wh | 1,706.07 BTU |
| 1,000 Wh | 3,412.14 BTU |
What Each Unit Is
BTU (BTU) — the energy to raise one pound of water by one degree Fahrenheit, or 1,055 joules. The imperial thermal unit, still standard for US heating, cooling and gas.
Watt Hours (Wh) — one watt sustained for one hour, or 3,600 joules. The practical electrical energy unit, following the adoption of the watt.
A Sense of Scale
A window air conditioner is 5,000–12,000 BTU/h- US furnaces are rated in BTU
- A phone battery holds 12–20 Wh
- A laptop battery is 50–100 Wh
Doing It in Your Head
Multiply by 5, then divide by 17. That is off by 0.36% — close enough to judge a
distance, a weight or a price, and not close enough to sign off on a drawing.
Exact Mental shortcut 2.9307 Wh 2.9412 Wh 29.3071 Wh 29.4118 Wh
Precision
The factor 0.293071070172 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.
In Code
`javascript
const btuToWattHour = (value) => value * 0.293071070172;
``
Where This Conversion Comes Up
- Nutrition
- Electricity
- Fitness
- Heating
- Fuel
How Many Decimals Do You Need?
Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 BTU with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 BTU becomes | Error |
|---|---|---|---|
| 0 | 0 | 0 | 100.0000% |
| 1 | 0.3 | 41.1 | 2.3642% |
| 2 | 0.29 | 39.73 | 1.0479% |
| 3 | 0.293 | 40.141 | 0.0243% |
| 4 | 0.2931 | 40.1547 | 0.0099% |
The right number of significant figures is set by your input, not by the converter. If you measured btu to three significant figures, the answer in watt hours is only good to three — writing more digits claims precision the measurement never had.