Estimate how long a tank or battery lasts under your specific load.

1 · Your setup

Continuous load (watts)

Generator (fuel) Battery

Fuel type Tank / fuel supply (gallons)

2 · Estimated runtime

A rough planning estimate. Real runtime varies with load profile, fuel quality, engine efficiency, temperature, and inverter losses. Generator model assumes ~3.6 kWh electrical output per gallon of gasoline (~3.0 for propane); battery model assumes 90% usable capacity. Estimates only.

Keep planning — related tools

Blackout runway timer →

Live countdown of how long your fuel lasts.

Fuel-type comparison →

Gas, propane, diesel, inverter, or battery side by side.

Whole-home load sizer →

Size a generator from your real appliance load.