01 / AVERAGE LOAD
Convert usage into watts
Energy-label mode converts daily kWh into a 24-hour average. Running-watts mode multiplies compressor watts by its duty cycle. Learn how to measure both correctly in our refrigerator wattage guide.
Real-world refrigerator planning
Refrigerator Backup Calculator
Estimate how long a power station or battery can keep your refrigerator running—using its energy label or measured running watts, with real efficiency and inverter limits included.
Two calculation modesStartup surge checkHot-room adjustment
Calculate your refrigerator runtime
For the best estimate, use the kWh per day printed on your appliance energy label. Use running-watts mode when you have a meter reading and realistic compressor duty cycle.
How the estimate works
The calculator separates energy use from inverter compatibility so a long runtime estimate never hides a startup problem.
02 / REAL CAPACITY
Allow for system losses
Usable battery percentage sets available watt-hours, while inverter efficiency increases the battery-side draw needed to support the refrigerator load.
03 / MOTOR START
Check surge separately
A refrigerator compressor can demand far more power for a moment at startup, so continuous and surge limits are checked independently.
Runtime = Battery Wh × Usable % ÷ ((Adjusted average refrigerator watts ÷ Efficiency %) + inverter idle watts)
Food safety is a separate clock
An unopened refrigerator generally keeps food safe for about four hours during an outage. Keep the door closed and follow official guidance for food held above 40°F (4°C). See FoodSafety.gov’s power-outage guidance. The electrical runtime estimate does not certify food safety.
Refrigerator backup questions
Why does my refrigerator use less than its running watts?
The compressor cycles on and off. Energy-label consumption already includes normal cycling, while running-watts mode estimates it through the duty-cycle percentage.
What startup surge should I enter?
Use the manufacturer’s locked-rotor or startup figure when available. A plug-in power meter with surge capture is better than guessing.
Does a hotter room reduce runtime?
Usually yes. The compressor may run longer, increasing average consumption. Use the hot-room adjustment for heat, weak seals or frequent door opening.
Can solar panels extend the estimate?
Yes, but this calculator intentionally excludes incoming solar because weather and charging limits vary. Treat the result as battery-only runtime.
OPTIONAL SHOPPING SHORTCUTS
Compare refrigerator backup options
Use your calculated watt-hours and startup surge as the requirements. A product is suitable only if both its usable capacity and inverter surge rating meet them.
Compare on AmazonBrowse refrigerator backup power stationsExplore JackeryCheck capacity and surge specificationsExplore BLUETTICheck capacity and surge specifications
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