Wh ↔ kWh ↔ Joules

How to use this calculator

Energy units relate by fixed factors: kWh = Wh / 1000 and J = Wh × 3600 (since 1 W = 1 J/s and one hour = 3600 s). Enter a value in any of the three fields — Wh, kWh, or J — and all three stay in sync in real time.

What it means in a real circuit

Wh is the natural battery unit (a 3.7 V, 1 Ah Li‑ion cell is 3.7 Wh); kWh is how the grid bills electricity (1 kWh = 1 "unit"); and joules is the SI unit of energy. Converting between them is constant when sizing a battery for a daily energy budget, comparing a car battery to a phone battery, or converting a generator's output into stored energy.