Joules to Watt-hours Converter
Common Conversions
| J | Wh |
|---|---|
| 1 | 0.000278 |
| 100 | 0.02778 |
| 1000 | 0.2778 |
| 3600 | 1 |
| 10000 | 2.778 |
| 36000 | 10 |
| 100000 | 27.78 |
| 360000 | 100 |
| 1000000 | 277.8 |
| 3600000 | 1000 |
| 10000000 | 2778 |
Why this conversion matters in chemistry
One watt-hour is just 1 W sustained for 3600 s — exactly 3600 J by construction. Capacitor-discharge energies in laser-flash photolysis show up in joules; battery and supercapacitor specs run in watt-hours. A 500 J flashlamp discharge is 0.139 Wh — a useful figure when sizing a backup-power system that has to safely dump a charged capacitor bank during a power outage. The same factor connects electrochemistry: a Faraday's worth of charge through a 1 V potential takes 96,485 J, which works out to 26.80 Wh per mole of electrons.
Formula
Worked Examples
The defining identity — one watt-hour is exactly 3600 J by construction.
One kilojoule expressed in watt-hours — about a third of a Wh, useful as a quick sanity check.
The energy of one Faraday of charge driven through 1 V — the reference value behind any electrolysis calculation per mole of electrons.
100 milliwatt-hours — the energy in a small button-cell battery.