Pick appliances, adjust the watts and hours to match your own (labels or a plug-in watt meter beat our typical figures), and the result updates as you type.
Appliance
Avg watts
Hours/day
Running W
Surge ×
How to read the columns
- Avg watts: average draw over the hours used. For fridges and freezers this already includes on/off cycling, so it's lower than the running watts.
- Running W: the draw while the device is actually on. It's used to check continuous output.
- Surge ×: the starting multiplier for motors and compressors. We use 2.5–4× for those presets and 1× for electronics and heaters.
Limits of this tool: It's a planning estimate. Real runtimes vary with temperature, battery age, inverter idle draw, and how your appliances actually behave. Wattage presets are typical figures, not measurements of your devices. The tool doesn't account for solar recharging; see the RV guide for that.
Want the reasoning behind the math? Read how to size a power station.