Home Battery Backup Runtime Calculator

Estimate how long a home battery or portable power station could run your essentials during an outage. Results are approximate.

Power stations often list Wh; home batteries often list kWh.
Example: 1000 Wh (1 kWh).
Use “appliances” if you’re not sure about watts.
Example: 120 W (router + lights + phone charging).
Formula

Usable energy ≈ capacity × 85%. Runtime (hours) ≈ usable energy (Wh) ÷ average load (W).