๐ Household
Generator Wattage Calculator
Motors draw a surge of two to three times their running watts for a second or two when they start. A generator has to cover the largest single surge plus everything else already running, which is why a fridge and a well pump together need more capacity than their labels suggest.
How it works
Total running watts needed
Largest motor starting watts
Safety margin
Peak surge watts
Recommended generator size
Recommended generator size
Frequently asked questions
How do I use the Generator Wattage Calculator?
Fill in the fields above โ the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.