Why is my real runtime shorter?

High discharge rates, temperature, aging, and Peukert effects reduce usable capacity compared with this simple model.

Pick one path: either direct Wh, or Ah×V. The tool converts Ah×V to Wh before applying DoD and η.

Battery Runtime Calculator

Computes hours of operation for a constant average load using effective energy E_eff = E_wh × DoD × η divided by load power. Energy can be entered directly in watt-hours or as amp-hours times nominal volts. Peukert, temperature, and chemistry-specific curves are not modeled.

Free · No limits · Runs in your browser

How to use

1Enter stored energy as watt-hours, or as amp-hours with a nominal voltage.
2Enter average load power in watts.
3Adjust efficiency and depth-of-discharge factors if they apply.
4Read estimated runtime in hours.

Frequently asked questions

Why is my real runtime shorter?: High discharge rates, temperature, aging, and Peukert effects reduce usable capacity compared with this simple model.
Can I mix Wh and Ah?: Pick one path: either direct Wh, or Ah×V. The tool converts Ah×V to Wh before applying DoD and η.