Watt Hours to BTU
Convert watt hours (Wh) to btu (BTU). Both measure work and power, and the conversion comes up in nutrition, electricity, fitness work.
The Formula
``
btu = watt hours × 3.41214163313
watt hours = btu × 0.293071070172
`
One watt hour is 3.4121 btu, and one BTU is 0.293071 watt hours.
Conversion Table
| 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 |
The Other Direction
| 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 |
What Each Unit Is
Watt Hours (Wh) — one watt sustained for one hour, or 3,600 joules. The practical electrical energy unit, following the adoption of the watt.
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.
A Sense of Scale
A phone battery holds 12–20 Wh- A laptop battery is 50–100 Wh
- A window air conditioner is 5,000–12,000 BTU/h
- US furnaces are rated in BTU
Doing It in Your Head
Multiply by 17, then divide by 5. 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 34.1214 BTU 34 BTU 341.2142 BTU 340 BTU
Precision
The factor 3.41214163313 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 wattHourToBtu = (value) => value * 3.41214163313;
``
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 Wh with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 Wh becomes | Error |
|---|---|---|---|
| 0 | 3 | 411 | 12.0787% |
| 1 | 3.4 | 465.8 | 0.3558% |
| 2 | 3.41 | 467.17 | 0.0628% |
| 3 | 3.412 | 467.444 | 0.0042% |
| 4 | 3.4121 | 467.458 | 0.0012% |
The right number of significant figures is set by your input, not by the converter. If you measured watt hours to three significant figures, the answer in btu is only good to three — writing more digits claims precision the measurement never had.