Wh to Ah Calculator
Convert Wh to Ah by dividing the energy by the battery voltage: Ah = Wh / V. Formula, worked example and a table of typical values.
Try your own numbers
Estimate only. Not engineering or safety advice. Check the result against the applicable standard and the equipment data, and have a competent engineer review it before it is relied on. Terms of use.
Open in the calculator with these values
Formula
Worked example
| Input | Value |
|---|---|
| Nominal voltage | 12 V |
| Energy | 1,200 Wh |
- mAh = Wh × 1000 / V = 1,200 Wh × 1000 / 12 V = 100,000 mAh
Typical values
| Energy (Wh) | Battery capacity (Ah) |
|---|---|
| 12 | 1 |
| 60 | 5 |
| 120 | 10 |
| 600 | 50 |
| 1,200 | 100 |
| 2,400 | 200 |
Other inputs are the same as in the worked example above.
Assumptions
- Nominal (mid-discharge) voltage, not the full-charge voltage
- Constant voltage over the discharge
Cells in series add voltage (3 Li-ion cells = 11.1 V) and keep the cell capacity; cells in parallel add capacity and keep the cell voltage. Use the pack voltage. Rated energy is not usable energy: depth of discharge, converter losses and temperature reduce it.
Frequently asked questions
How do I convert Wh to Ah?
Wh = mAh × V / 1000; mAh = Wh × 1000 / V. Worked example: Nominal voltage 12 V, energy 1,200 Wh gives 100 Ah.
What do I need to enter?
Enter battery capacity, nominal voltage and energy. Leave blank the value you want to find, and the form solves for it. Change the unit of a value with its selector and the result stays the same.
Why do I need the voltage to convert Ah and Wh?
Ah is charge (current × time) and Wh is energy (power × time). They are linked by the battery voltage, so one cannot be converted to the other without it.
Which voltage should I use for a battery bank?
Use the nominal voltage of the whole bank. Batteries in series add voltage (four 12 V batteries make 48 V) and keep the Ah; batteries in parallel add Ah and keep the voltage. The result is rated energy, not usable energy: depth of discharge, inverter losses and temperature reduce it.
How accurate are the results?
Every figure comes from the same tested engine as the Elecmetric calculators and is meant for estimating. Check design values against the standard and the equipment data you work to.
Related
Next steps in a design: Joules to VoltskW to kWhEnergy Unit Converter
Opposite direction: Ah to Wh
Also see: Ah to kWh kWh to Ah kW to Wh Wh to kW
Formula guides: Battery Capacity ConverterAh to mAh ConverterBattery Pack Formulas: Series and Parallel
All 78 conversionsmAh to Wh and Wh to mAh in Elecmetric