What size generator do you need to run a refrigerator?

Updated 2026-10-31 · Sources linked inline

For a refrigerator on its own, plan on a generator with at least 2,000 to 2,200 starting watts and 1,000 or more rated running watts. That covers even the most conservative published figure for a fridge. If you want to run a freezer, lights, a router and a sump pump too, you move into the 3,000-watt class. The reason is the compressor's starting surge, not its running draw.

How this guide was made: this is a research guide built on manufacturer specifications and federal guidance, with sources linked throughout. We haven't bench-tested any of the equipment mentioned, and we don't claim to. The examples below are arithmetic on published figures.

Why the starting number decides

A refrigerator compressor is a motor. When it starts, it briefly draws several times its running power. A generator that can't supply that surge will trip or stall, even if its running rating is far above the fridge's average draw. Published figures:

The spread is wide on purpose. The low numbers reflect newer, efficient models; the high numbers build in margin for older fridges. For background on average draw and daily energy, see how many watts a refrigerator uses.

The sizing method

Our generator size calculator uses two methods and lets you add optional headroom:

• Standard method: total running watts of everything on at once, plus the largest single start surge (starting minus running watts), because motors rarely start at the same instant.
• Conservative worksheet method: total running watts plus the largest listed starting figure.
• Headroom: a common-practice margin (our calculator offers 0, 10 or 20%) so you don't run at the generator's limit. This is an assumption, not a requirement from the sources.

You can also estimate from the nameplate. Amps × volts gives the maximum draw: a fridge labeled 6 A on 120 V is about 720 W at most while running. Starting surge isn't on the label, so use the published figures above.

Worked examples

All use the upper end of each published range, as the calculator does.

Example 1: refrigerator only

Example 2: fridge, freezer, lights and router (Champion upper figures for fridge 400/1,200 and freezer 500/1,000; 100 W of LED lights; 20 W router)

• Running: 400 + 500 + 100 + 20 = 1,020 W.
• Largest start extra: fridge 800 W (freezer is 500 W).
• Minimum starting watts: 1,020 + 800 = 1,820 W. Conservative: 1,020 + 1,200 = 2,220 W.
• With 20% headroom: about 1,224 W running, 2,184 W starting.

Example 3: add a 1/3 hp sump pump (Honda 800 / 1,300 W, start extra 500)

• Running: 1,020 + 800 = 1,820 W.
• Largest start extra is still the fridge at 800 W, so minimum starting watts: 2,620 W. Conservative: 1,820 + 1,300 = 3,120 W.
• With 20% headroom: about 2,184 W running, 3,144 W starting.

See how many watts a sump pump uses for the pump side.

Which generator size fits?

Match your totals to a spec sheet that lists both a continuous (rated) and a maximum (starting) figure. As one example of a small inverter generator, Honda's EU2200i lists 1,800 W rated and 2,200 W maximum on 120 V, a 0.95 gallon tank, and run times of 3.2 hours at rated load and 8.1 hours at 1/4 load (Honda). Compare that to the examples:

Those fits are arithmetic on the published numbers, not a guarantee. Real fridges and generators vary, and Honda's own materials stress that power management (starting items at different times) lets a smaller unit do more.

Two practical points. First, use an inverter-type generator if you power electronics; the spec sheet for Honda's EU2200i Companion lists "advanced inverter technology provides reliable power to computers and other sensitive equipment" (Honda spec sheet). Second, a conventional open-frame generator of the same rating is typically louder and heavier, but costs less; check its spec sheet.

Run it in cycles to save fuel

A refrigerator doesn't need to run all night. FoodSafety.gov says a closed refrigerator keeps food safe up to 4 hours and a full freezer about 48 hours (24 hours if half full) (FoodSafety.gov). That gives you room to run the generator for part of each few hours rather than continuously, if you also confirm temperatures with a thermometer. Treat this as an approach to try and verify, not a food-safety guarantee: keep the fridge at or below 40 °F, and when in doubt, throw it out.

Fuel math: Honda doesn't state the watts behind "1/4 load." If it is a quarter of the 1,800 W rating (450 W), a fridge-only load of a few hundred watts would burn less fuel per hour than that, so a tank should last longer than 8.1 hours. That is an inference from the published numbers, not a measured result; the manual and a real-world check will tell you more.

Cords, fuel and safety

• Place the generator outdoors and more than 20 feet from windows, doors and vents. Never in a garage. See generator carbon monoxide safety.
• Use a heavy-duty, outdoor-rated extension cord whose wattage rating exceeds the load, and check it for damage. CPSC also warns never to backfeed a house through a wall outlet (CPSC).
• Fill the tank before the storm and follow the generator manual's refueling instructions.
• Plug the fridge directly into the generator or a heavy-duty cord rated for the load.

What if you'd rather use a battery?

A battery works if its surge rating covers the compressor start and its capacity covers the hours. Our fridge guide has a worked runtime table, and generator vs power station compares the options. For a whole-house plan, see what size generator to run a house.

Common mistakes

• Sizing to running watts. A 1,000 W generator can run a fridge's 200 W draw all day and still fail to start the compressor.
• Forgetting everything else on the circuit. The fridge shares the generator with every light, charger and cord you add.
• Using a thin cord. An undersized or damaged cord overheats and drops voltage, which makes motor starts harder.
• Never trying the setup. Run it once in daylight before the storm, outdoors and well away from the house, with the fridge plugged in, and watch the generator's load indicator if it has one.
• Trusting one chart. Charts disagree because fridges differ. Your fridge's nameplate beats any table.

Summary

Use the generator size calculator with your own appliances, check your fridge's data plate and build the rest of the plan with the Alabama outage checklist.