Flip the switches for everything you need to power — from the fridge and well pump to loads other calculators forget, like egg incubators, reptile lamps, aquariums, and MIG welders. We’ll total your running and starting watts and tell you exactly what generator class to buy.
Generator Sizing Calculator
Wattages shown are typical estimates — always verify against your appliance nameplate or manual. Starting (surge) watts assume only one motor starts at a time. We add a 25% headroom margin so your generator runs below max load.
Every appliance you toggle on adds its typical running watts to your total. For surge, we use the industry-standard method: your running total plus the single largest starting surge among your selections, because in practice motors and compressors don’t all start at the same instant. We then add a 25% headroom margin — generators shouldn’t live at max load — and round up to the nearest 500W to give you a realistic size target.
Most wattage calculators stop at lights, TVs, and refrigerators. But if you keep chickens, reptiles, fish, bees, or a greenhouse, an outage threatens loads that most sizing guides never mention — and those loads are usually continuity-critical. An incubator that cools mid-hatch or a tank heater that drops for a night can mean real losses. That’s why the Homestead & Critters panel exists, and why the calculator flags sensitive and round-the-clock loads with specific advice instead of just a number.
Once you have your number, head to our full sizing guide for a deeper walkthrough, or jump straight into the category that matches your recommendation: inverter generators for quiet electronics-safe power, dual-fuel units for long outages, solar generators for silent indoor-safe backup, or home standby systems for whole-house automatic coverage.