Watt Hours to Joules
A watt-hour is the energy used by a one-watt device running for one hour, used to rate small batteries. The joule is the SI unit of energy, defined as the work done by one newton over one meter. 1 Wh equals 3,600 J, so converting between them is a matter of multiplying by that fixed factor — type any value into the converter below and both sides update instantly as you type.
Both units belong to energy, measured here against energy's base unit (J) — every other energy unit on this site converts through that same reference point, which is why the table below can also be read as a quick cross-check against nearby values.
Formula
J = Wh × 3,600
Wh = J × ≈0.000277778
Worked example: 5 Wh × 3,600 = 18,000 J.
Conversion table
| Watt-hour (Wh) | Joule (J) |
|---|---|
| 1 Wh | 3,600 J |
| 2 Wh | 7,200 J |
| 3 Wh | 10,800 J |
| 5 Wh | 18,000 J |
| 10 Wh | 36,000 J |
| 20 Wh | 72,000 J |
| 25 Wh | 90,000 J |
| 50 Wh | 180,000 J |
| 100 Wh | 360,000 J |
| 250 Wh | 900,000 J |
| 500 Wh | 1,800,000 J |
| 1,000 Wh | 3,600,000 J |
Frequently asked
- How many Joules in a watt-hour?
- 1 Wh equals 3,600 J.
- How do I convert Watt-hours to Joules?
- Multiply the value in Wh by 3,600 to get J. The converter above does this instantly as you type.
- Is the conversion exact?
- Yes — Watt-hour and Joule are both defined by a fixed conversion factor to energy's base unit (J), so the result shown is exact to the precision displayed, not an approximation.