Generator Size for a Well Pump
Find the right generator for a well pump. Enter its running and startup watts to see the recommended generator size, with headroom for the motor surge.
Runs locally in your browser — no upload, no trackingTry: Well pump running watts=1000, Well pump startup (surge) watts=2200 → 1,000 W, 2,200 W, 2,640 W, 3.5 kW
How to use
A ½ HP well pump typically draws about 1,000 running watts but surges to 2,200 when the motor starts. The generator must handle that starting spike or the pump will not spin up. Enter your appliance's running and startup (surge) watts and press Calculate. The recommended size adds a 20% safety margin to the surge so the generator is never running at its limit.
These are typical figures — the plate on your well pump may read differently. If you run more than one device together, use the multi-appliance calculator instead.
FAQ
What size generator will run a well pump?
A ½ HP well pump needs roughly 1,000 running watts and 2,200 starting watts. Plan on at least a 3.5 kW generator, and more if the pump shares the generator with a fridge or furnace.