Battery Capacity Converter
Convert battery capacity between mAh, Ah, Wh, and kWh at any voltage.
Compare phone batteries, power banks, and EV packs and calculate runtime for any device.
Enter voltage and any capacity value — the others update instantly.
Battery capacity can be measured in amp-hours (Ah) or watt-hours (Wh). Converting between them requires knowing the voltage.
Core formulas:
- Wh = Ah × Voltage
- Ah = Wh / Voltage
- mAh = Ah × 1,000
- kWh = Wh / 1,000
Common battery voltages:
| Battery Type | Nominal Voltage |
|---|---|
| AA/AAA (NiMH) | 1.2 V |
| AA/AAA (Alkaline) | 1.5 V |
| Li-ion cell (18650) | 3.7 V |
| Phone battery | 3.7-3.85 V |
| Laptop battery | 11.1-14.8 V |
| Car battery (12V) | 12.6 V |
| EV battery pack | 350-800 V |
Example conversions:
- Phone: 5,000 mAh at 3.7V = 18.5 Wh
- Power bank: 20,000 mAh at 3.7V = 74 Wh
- Laptop: 56 Wh at 11.1V = 5,045 mAh
- Tesla Model 3: 60 kWh at 350V = 171.4 Ah
Airline limit: Most airlines allow batteries up to 100 Wh in carry-on. Batteries 100-160 Wh need airline approval.