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What size generator do you actually need?

Check the appliances that must run at the same time. We add the running watts, apply the single-largest starting surge (staggered starts), add 25% headroom, and recommend a size class — not a brand.

Build your load — check what must run at the same time

Totals update live. Surge math assumes staggered starts: plug loads in one at a time, largest motor last. 25% headroom applied.

Home Backup
Heating & Cooling
Water & Pumps
Kitchen
RV & Camping
Job Site

Recommended generator

Check some loads to start

    29 calculators, every number sourced

    Every page shows running and starting watts as ranges with named sources — manufacturer spec sheets, DOE data and established sizing charts — plus the 120/240V flag and the honest answer, even when it is “this load doesn’t belong on a portable generator”. Readhow the sizing math works, then check your own nameplates before you buy.

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    Our printable pre-storm checklist — fuel, cords, food-safety windows, safe placement — plus occasional emails when new calculators launch. No spam.

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