Estimate charging time, power and battery energy — accurately.
Real charging slows past ~80%, so full-charge times run a bit longer.
Typical maximum power of common charging standards.
| Standard | Max power | Voltage / current |
|---|
Figures are approximate maximums; actual output depends on the device and cable.
This calculator converts your battery capacity into watt-hours (capacity × voltage), then divides the energy it still needs by the charger's effective power (rated output × efficiency). The result is a realistic estimate of charging time, plus the energy added and the effective power reaching the battery.
The battery capacity is converted to watt-hours (capacity × voltage), and the energy needed is divided by the charger's effective power (output × efficiency).
Devices cap their own charging speed and slow down after about 80% to protect the battery, so real times can be longer than a linear estimate.
Use around 85% for wired charging and 70% for wireless, since some energy is always lost as heat during conversion.