How do you calculate amp-hours?
Multiply average current in amps by operating time in hours:
Ah = A × h
Example: a steady 10A load for 5 hours requires 50Ah. If you know watts instead, divide watts by voltage to find current, then multiply by time.
Amp-hour examples
Amps, amp-hours and voltage
Amps describe current now; amp-hours describe current over time. Ah alone does not state energy because voltage also matters. Use the watt-hour calculator when you need to compare batteries at different voltages.
How to interpret theoretical runtime
The simple relationship Ah ÷ A assumes all labeled capacity is available at a steady current. The optional usable-capacity and reserve fields make it more conservative, but the result still omits voltage conversion, inverter losses, temperature and battery behavior. For those factors, use the advanced battery runtime calculator or the dedicated 12V battery runtime calculator.
Amp-hour calculator FAQ
How do you calculate amp-hours?
Multiply average current in amps by time in hours: Ah = A × h.
How do you convert watts to amp-hours?
Multiply watts by hours, then divide by voltage: Ah = (W × h) ÷ V.
How many amp-hours are in 1 kWh?
It depends on voltage. 1kWh is about 83.33Ah at 12V, 41.67Ah at 24V or 20.83Ah at 48V.
What is the difference between amps and amp-hours?
Amps measure current at a moment in time. Amp-hours measure current delivered over time.