A plug-in power and energy monitor showing a wattage reading

Guide hub

Sizing & Wattage

Buying the wrong size is the most common generator regret. Too small and the fridge or well pump trips it every time it starts; too big and you are paying for fuel you never use. The fix is simple arithmetic once you know the difference between running watts and starting watts.

Try the wattage calculator for a quick total, then read what size portable generator runs a whole house or standby sizing for a 2,400 sq ft home. Single appliances have their own quirks; sizing for a refrigerator and running a heat pump are good examples. To plan fuel, use the fuel run-time calculator.

Start with these