Convert Watt-hours to BTU
1 watt-hour (Wh) equals 3.412141633 British thermal units (BTU).
1 Wh = 3.412141633 BTU
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk watt-hour to BTU converter to paste a column from Excel.
How to Convert Watt-hour to BTU
- 1 Wh = 3.412141633 BTU
- 1 BTU = 0.2930710702 Wh
- Example: convert 15 Wh to BTU: 15 Wh = 15 × 3.412141633 BTU = 51.1821245 BTU
Reference conditions. BTU: International Table BTU (BTU_IT), 1055.05585262 J exactly.
Formula
BTU = Wh × 3.412141633128
Derivation from SI units:
- 1 Wh = 1 W × 3600 s = 3600 J
- 1 BTU_IT = 1055.05585262 J (exact)
- 1 Wh = 3600 J ÷ 1055.05585262 J per BTU = 3.412141633128 BTU
Both units are defined exactly, so the factor is exact. Watt-hour definition: watt-hour; BTU definition: British thermal unit.
Worked examples
- A reading of 20 Wh converts to 68.24283266 BTU.
20 Wh × 3.412141633 = 68.24283266 BTU - A value of 100 Wh is 341.2141633 BTU.
100 Wh × 3.412141633 = 341.2141633 BTU
Watt-hour to BTU conversion table
| Watt-hours (Wh) | BTU |
|---|---|
| 1 Wh | 3.412141633 BTU |
| 5 Wh | 17.06070817 BTU |
| 10 Wh | 34.12141633 BTU |
| 15 Wh | 51.1821245 BTU |
| 20 Wh | 68.24283266 BTU |
| 50 Wh | 170.6070817 BTU |
| 60 Wh | 204.728498 BTU |
| 75 Wh | 255.9106225 BTU |
| 100 Wh | 341.2141633 BTU |
| 160 Wh | 545.9426613 BTU |
| 500 Wh | 1706.070817 BTU |
| 1000 Wh | 3412.141633 BTU |
Where it's used
Watt-hours are used for battery capacity (phone ≈ 15 Wh; airline limit 100 Wh per power bank), while British thermal units appear in furnace, boiler and fuel ratings in the US. Both measure energy, work and heat, so the conversion is a fixed factor.
Watt-hour to other energy units
| Conversion | 1 Wh equals |
|---|---|
| watt-hour to joule | 3600 J |
| watt-hour to kilojoule | 3.6 kJ |
| watt-hour to megajoule | 0.0036 MJ |
| watt-hour to calorie | 860.4206501 cal |
| watt-hour to kilocalorie | 0.8604206501 kcal |
| watt-hour to kilowatt-hour | 0.001 kWh |
| watt-hour to BTU | 3.412141633 BTU |
| watt-hour to therm | 0.00003412956341 thm |
| watt-hour to electronvolt | 2.246943267 × 10²² eV |
| watt-hour to foot-pound | 2655.223737 ft·lbf |
| watt-hour to erg | 36000000000 erg |
Frequently asked questions
How many British thermal units are in 1 watt-hour?
1 Wh = 3.412141633 BTU.
How do I convert watt-hours to British thermal units?
Multiply the value in Wh by 3.412141633. For example, 15 Wh × 3.412141633 = 51.1821245 BTU.
Is the Wh to BTU conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "watt hour (W·h)".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "British thermal unit_IT (Btu_IT)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Watt-hours to BTU. Retrieved October 17, 2026, from https://scientificconverters.com/energy/watt-hours-to-btu/
IEEE
Scientific Converters, "Convert Watt-hours to BTU," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/watt-hours-to-btu/