How to calculate the Watt Hours (Wh) of a lithium battery

If you intend to ship or you are traveling by air with lithium cells, batteries or battery packs, you will need to know their Watt-hour rating. This applies to lithium metal batteries (disposable) and lithium ion batteries (rechargeable).

Lithium-ion battery showing Watt-hour rating
This is usually stated on the battery itself. If not, you can calculate it as Volts x amp hours (Ah).

example 1: an 11.1 volt 4,400 mAh battery – first divide the mAh rating by 1,000 to get the Ah rating – 4,400/1,000 – 4.4ah. You can now calculate as – 4.4Ah x 11.1 volts = 48.8Wh

example 2: a 12 volt 50 Ah battery – 50 Ah x 12 volts = 600Wh