Calculate watt-hours from watts and runtime, amps and volts, battery amp-hours, or kilowatt-hours. This calculator helps estimate energy storage, battery capacity, device runtime, kWh conversion, and electricity cost.
Energy from power:
The calculator multiplies watts by hours to estimate watt-hours.
Battery capacity:
For batteries, it multiplies amp-hours by volts to estimate stored watt-hours.
Usable energy:
Efficiency and usable battery percentage are applied to estimate usable watt-hours and runtime.
A watt hours calculator helps estimate battery capacity, stored energy, device runtime, appliance energy use, and small power system needs.
It can help with power stations, solar batteries, RV systems, camping setups, laptops, refrigerators, lighting, electronics, e-bikes, and off-grid energy planning.
Your result shows total watt-hours, usable watt-hours, kilowatt-hours, estimated cost, runtime hours, amp-hours, watts, volts, efficiency, usable battery percentage, and comparison item estimates.
Multiply watts by hours. For example, a 100 watt device running for 8 hours uses 800 watt-hours.
Multiply battery amp-hours by battery voltage. A 12V 100Ah battery has about 1,200 watt-hours before efficiency and usable-capacity adjustments.
Watts measure power. Watt-hours measure energy used or stored over time.
There are 1,000 watt-hours in 1 kilowatt-hour.