Joules to watt-hours converter
Convert joules to watt-hours with an editable calculator, worked example, formula and reference table. Check the unit definitions before you convert.
Updated · How we checkUse a decimal point, such as 2.5. Enter a value in J; the result is in Wh.
Formula
Worked example
Convert 3600 J to Wh:
3600 J ≈ 1 Wh
Multiply your J value by the factor above. The calculator uses the full conversion factor before rounding the displayed answer.
Joules to watt-hours table
Reference values rounded to 10 significant digits. Use the converter above for other amounts.
| Joules (J) | Watt-hours (Wh) |
|---|---|
| 0.1 | ≈ 0.00002777777778 |
| 0.5 | ≈ 0.0001388888889 |
| 1 | ≈ 0.0002777777778 |
| 2 | ≈ 0.0005555555556 |
| 5 | ≈ 0.001388888889 |
| 10 | ≈ 0.002777777778 |
| 25 | ≈ 0.006944444444 |
| 50 | ≈ 0.01388888889 |
| 100 | ≈ 0.02777777778 |
| 1000 | ≈ 0.2777777778 |
Understanding joules
The joule measures energy or work. One watt sustained for one second transfers one joule. Joules are not a measure of power without a time interval.
Understanding watt-hours
One watt-hour equals 3,600 joules. It is the energy transferred by one watt over one hour. Battery energy estimates also depend on usable capacity and losses.
Precision and rounding
The calculator keeps decimal precision during the conversion. Displayed values use up to 10 significant digits; an approximation sign marks the reference results. Keep extra digits until your final measurement or purchase decision.
References
Definitions and method references. Example rates and prices on this page are editable assumptions.