mAh to Wh Calculator

Battery capacity is quoted in mAh, but the work a battery does is in Wh. Multiplying mAh by nominal cell voltage gives you the figure that actually drives runtime calculations, transport classification under UN 38.3, and the dollars-per-kWh number a procurement team needs to compare modules from different suppliers on a fair basis. A 5,000 mAh cell at 3.7 V (18.5 Wh) is a very different battery to a 5,000 mAh cell at 12 V (60 Wh), and the bill of materials reflects that.

For an industrial site running portable comms kit, mobile IoT sensors, or temporary instrumentation, the mAh to Wh conversion is what turns a vendor spec sheet into a deployment plan. If a sensor draws 200 mW on average and you need a six-month service interval, that is around 850 Wh of useful capacity required, plus margin for cold ambient, end-of-life capacity fade and discharge curve flatness. Sized in Wh, the answer maps directly onto the cell formats available, and the kit you order has a fighting chance of lasting the cycle.

For battery energy storage system (BESS) procurement at the I&C scale, the same conversion sits underneath the modular pricing. Suppliers will quote a price per kWh of usable capacity, but the underlying cells are characterised in mAh at a defined C-rate. Reconciling the two is what reveals whether the headline price is on rated cell capacity (optimistic) or on end-of-life usable energy at the system level (realistic), and which is the right number for a 10 or 15 year financial model on a behind-the-meter battery.