Wh to Ah and Ah to Wh converter
Energy arithmetic requires nominal battery voltage. Equal mAh ratings at different voltages do not represent equal energy.
Enter nominal voltage and convert.
Choose the voltage that belongs to the rating
Use the battery's relevant nominal voltage from its specifications. Do not automatically use the AC outlet voltage or a USB charging voltage. A battery's internal energy rating and its output-port settings describe different parts of the device.
For example, a power bank may state mAh at its cells' nominal voltage. Multiplying that rating by an unrelated USB output voltage would overstate its nominal energy. If the voltage associated with the rating is unknown, the conversion is unresolved.
Formulas
Wh = Ah × nominal volts. Ah = Wh ÷ nominal volts. Divide mAh by 1,000 to obtain Ah. The converter supports both directions; label the unit you enter carefully.
Worked example
100 Ah at 12.8 V equals 1,280 Wh. 10,000 mAh is 10 Ah; at 3.7 V it equals 37 Wh. These are nominal energy conversions before any usable-capacity or output losses.
Calculated with the same formulas as the interactive tool. Inputs are illustrative and results are rounded for display.
Can I compare two batteries by Ah alone?
Only with the voltage context. Equal Ah at different nominal voltages represents different energy. Wh is usually the more useful first comparison for stored energy, followed by capacity availability, output capability, and connection requirements.
Does this tell me usable runtime?
No. The conversion does not account for reserve, capacity reduction, conversion efficiency, idle draw, or appliance power. Take the resulting Wh to the runtime calculator with explicit load assumptions. Read watts versus watt-hours if you are deciding whether a label describes energy or instantaneous power.