Food stays safe in a closed refrigerator for about 4 hours during a power outage. A full freezer holds a safe temperature for about 48 hours, and a half-full freezer for about 24 hours, as long as the doors stay shut. After 4 hours without power, move perishables to a cooler with ice, and throw out refrigerated food that has been above 40 degrees Fahrenheit for more than 2 hours.
Those four numbers come from USDA, CDC, and FDA food safety guidance, and they are worth memorizing, because the first thing almost everyone does when the lights go out is open the fridge to check on things. Every time the door opens, the clock runs faster.
This guide covers how long food lasts in the fridge without power, how long the freezer holds, exactly what to keep and what to throw out afterward, and the inexpensive ways to buy your food a lot more time.
How Long Does Food Last in a Fridge Without Power?
Food lasts about 4 hours in a refrigerator without power if the door stays closed. A modern fridge is well insulated, but once its interior climbs above 40 degrees Fahrenheit, bacteria in perishable food begin to multiply quickly. That is why the 4-hour figure matters: It is roughly how long a closed fridge stays at or below 40 degrees on its own.
Opening the door cuts that window short, so keep it closed unless you are moving food into a cooler. If you expect the outage to run past 4 hours, transfer milk, meat, leftovers, and other perishables into a cooler packed with ice or frozen gel packs, enough to hold everything at 40 degrees or below. An appliance thermometer in the fridge takes the guesswork out, since it tells you the actual temperature rather than how cold things feel.
How Long Will a Freezer Keep Food Frozen Without Power?
A full freezer will keep food frozen for about 48 hours without power, and a half-full freezer for about 24 hours, as long as the door stays closed. The difference comes from thermal mass: In a full freezer, the frozen food itself helps keep neighboring items cold, while a half-empty freezer has more air to warm up.
That gives you a simple habit with a big payoff. Keep the freezer as full as you can year-round, filling empty space with jugs of water that freeze solid, and group food tightly together during an outage. Those frozen water jugs double as ice for your cooler and as clean drinking water once they thaw.
When the power comes back, check each item. Food that still contains ice crystals, or is at 40 degrees or below, can be safely refrozen or cooked, though some items may lose a little quality in texture.
What to Keep and What to Throw Out After a Power Outage
Once the power has been out for more than 4 hours and refrigerated food has been above 40 degrees for over 2 hours, some items become unsafe while others hold up fine. Here is how the common categories break down.
|
Food |
Above 40°F for 2+ hours |
Why |
|---|---|---|
|
Raw or cooked meat, poultry, and seafood |
Throw out |
High-risk foods where bacteria grow quickly |
|
Milk, cream, yogurt, and soft cheeses |
Throw out |
Dairy spoils fast once it warms |
|
Eggs and egg dishes |
Throw out |
A common source of foodborne illness |
|
Leftovers, cooked pasta, rice, and casseroles |
Throw out |
Moist, cooked foods are ideal for bacteria |
|
Deli meats, hot dogs, and luncheon meats |
Throw out |
Processed meats still spoil when warm |
|
Cut fruits and vegetables |
Throw out |
Cutting exposes the flesh to bacteria |
|
Hard cheeses such as cheddar and parmesan |
Usually keep |
Low moisture makes them more stable |
|
Butter and margarine |
Usually keep |
High fat and low moisture slow spoilage |
|
Whole, uncut fruits and vegetables |
Keep |
The skin protects the flesh |
|
Condiments such as ketchup, mustard, jelly, and peanut butter |
Keep |
Acidic or low-moisture products resist bacteria |
Two rules override the table. Never taste food to decide whether it is safe, because many bacteria that cause illness do not change the smell, taste, or look of food. And when you are unsure, throw it out. A few dollars of groceries is never worth a case of food poisoning.
How to Keep Food Cold Longer During a Long Outage
The 4- and 48-hour windows are the baseline, not the limit. A few inexpensive steps, most of them done before the outage, can stretch them dramatically.
Coolers and ice are the first layer. Keep at least one good cooler in the house and a few frozen jugs or gel packs in the freezer, so you can move perishables over the moment the 4-hour mark arrives. Dry ice is the second layer for a long outage: According to USDA and FDA guidance, about 50 pounds of dry ice will keep a full 18-cubic-foot freezer cold for roughly two days. Handle it only with insulated gloves, never touch it bare-handed or let it rest directly on food, keep the area ventilated, and never seal it in an airtight container, since it releases carbon dioxide gas.
The third layer is power. A portable power station can keep a refrigerator running through an outage, which ends the countdown entirely. A full-size fridge typically draws 100 to 200 watts while running, with a brief startup surge, and because it cycles on and off, a unit of around 1,000 watt-hours can usually keep it cold for well over half a day. Add a folding solar panel and you can recharge each day for a multi-day outage. Browse options in Backup Power and Power & Light, and size the unit to cover the fridge’s startup surge, not just its running watts.
Preparing Your Fridge and Freezer Before the Power Goes Out
The best time to protect your food is before a storm, when it takes a few minutes and almost no money. Put appliance thermometers in both the fridge and the freezer, and keep them at 40 degrees or below and 0 degrees or below respectively. When an outage is likely, turn both to their coldest settings a few hours ahead to build a cold buffer, fill empty freezer space with water jugs, and know where to buy dry ice or block ice locally before everyone else is looking for it.
It also helps not to depend entirely on refrigerated food. A stock of shelf-stable meals from Food Rations and stored water from water storage and filtration means a spoiled fridge is an inconvenience rather than a problem. That is the quiet work of outage planning: Done ahead, it keeps your family fed and your groceries safe before anything goes wrong.
The Fridge and Freezer Mistakes That Waste Food or Make People Sick
Most spoiled food after an outage, and most outage-related food poisoning, comes back to a handful of decisions rather than to bad luck.
The most common is opening the fridge repeatedly to check on things, which bleeds out the cold air that was buying you time. The second is not owning a thermometer, which forces guesswork about whether food stayed at 40 degrees. The third is the smell test, since dangerous bacteria often leave food looking and smelling normal. The fourth is refreezing food that fully thawed and sat warm, rather than checking for ice crystals or a temperature at or below 40 degrees. The last is waiting until the outage to look for ice, when stores nearby are often sold out or closed. Each one is easy to avoid with a little planning and a cheap appliance thermometer.
FAQ
How Long Does Food Last in a Fridge Without Power?
Food lasts about 4 hours in a refrigerator without power if the door stays closed. After that, the interior rises above 40 degrees Fahrenheit and bacteria in perishable food multiply quickly. If the outage will run longer than 4 hours, move perishables like milk, meat, eggs, and leftovers into a cooler with ice or frozen gel packs, and throw out refrigerated perishables that have been above 40 degrees for more than 2 hours.
How Long Will a Freezer Keep Food Frozen Without Power?
A full freezer keeps food frozen for about 48 hours without power, and a half-full freezer for about 24 hours, as long as the door stays closed. A full freezer lasts longer because the frozen food helps keep neighboring items cold. When power returns, food that still has ice crystals or is at 40 degrees Fahrenheit or below can be safely refrozen or cooked.
Can I refreeze food that thawed during a power outage?
Yes, if it still contains ice crystals or is at 40 degrees Fahrenheit or below. In that case it is safe to refreeze or cook, though some foods may lose quality in texture. Food that fully thawed and sat above 40 degrees for more than 2 hours should be thrown out rather than refrozen. A freezer thermometer makes this decision easy.
How much dry ice do I need to keep a freezer cold?
According to USDA and FDA guidance, about 50 pounds of dry ice will keep a full 18-cubic-foot freezer cold for roughly two days. Handle dry ice only with insulated gloves, never let it touch food directly, keep the area well ventilated, and never seal it in an airtight container, because it releases carbon dioxide gas as it warms.
How long can a power station run a refrigerator during an outage?
A full-size refrigerator typically draws about 100 to 200 watts while running, with a short startup surge, and cycles on and off through the day. A portable power station of around 1,000 watt-hours can usually keep it cold for well over half a day, and adding a folding solar panel lets you recharge daily for multi-day outages. Choose a unit whose surge rating covers the fridge’s startup draw.
