How Long Does Food Last in the Fridge Without Power? Safe Hours and What to Throw Out

Quick answer. A refrigerator keeps food safe for up to 4 hours without power if you keep the door closed. A full freezer holds a safe temperature for about 48 hours and a half full one for about 24 hours. After that, check temperatures. Perishable food that has been above 40°F (4°C) for more than 2 hours should be thrown out, and you should never taste food to decide.

When the lights go out, the fridge is usually the first thing people worry about after phones and heating. A full week of shopping can be lost in a single long outage, and the advice you hear from friends and neighbours is often a mix of guesses and old habits.

This guide sets out what the official food safety agencies actually say, food by food, and how to stretch the cold you already have. All the times and temperatures come from the USDA Food Safety and Inspection Service, the CDC and the FoodSafety.gov outage chart. We have not run our own fridge tests, and we do not add our own numbers to theirs.

The times to remember

Three numbers cover most outages. The CDC states them plainly. If the doors stay closed, food stays safe for up to 4 hours in a refrigerator, 48 hours in a full freezer and 24 hours in a half full freezer.

Appliance	Safe time with the door closed	Source
Refrigerator	Up to 4 hours	USDA, CDC, FoodSafety.gov
Full freezer	About 48 hours	USDA, CDC, FoodSafety.gov
Half full freezer	About 24 hours	USDA, CDC, FoodSafety.gov

These times depend on one thing above all, which is keeping the door shut. Every opening lets cold air fall out and warm kitchen air in. If you need something, decide what it is before you open the door, take it out quickly and close it again.

The times are also guides rather than guarantees. A fridge that was already warm, an old door seal or a hot summer kitchen will shorten them. That is why the agencies all say to judge food by temperature once the 4 hour mark has passed.

Why 40°F is the line that matters

Refrigerators are meant to run at 40°F (4°C) or below and freezers at 0°F (-18°C) or below. The USDA and CDC both give those targets. Once perishable food climbs above 40°F, bacteria can multiply faster, and FoodSafety.gov’s whole outage chart is built around food that has been at 40°F or above for more than 2 hours.

So the most useful thing you can do before an outage costs very little. Put an appliance thermometer in the fridge and another in the freezer. When the power comes back you can open the door, read the dial and know where you stand. Without one, you are left guessing how warm it got while you were asleep.

If you have a food thermometer, you can also check individual items. Anything perishable that reads above 40°F after a long outage belongs in the bin.

What to do the moment the power goes off

• Keep both doors closed. This is the single biggest factor in how long food lasts.
• Note the time. Write it down or take a photo of a clock so you know when the 4 hour window ends.
• Check your outage estimate. If your utility expects a long cut, start planning ice or a cooler now rather than at hour four.
• Get ice early if you can. The USDA suggests finding out in advance where to buy dry ice or block ice. It says 50 pounds of dry ice should hold an 18 cubic foot freezer for 2 days. Never touch dry ice with bare hands or let it touch food directly.
• Leave the freezer alone. A full freezer protects itself. The food inside acts as its own ice pack.

After 4 hours, move to a cooler

Once the fridge has been off for 4 hours, the CDC says to put refrigerated perishable foods in a cooler if you have one and ice is available. Add ice or frozen gel packs to keep the food at 40°F or below and top up the ice as it melts.

Start with the riskiest foods. Raw meat, poultry and fish, milk, eggs, soft cheeses and cooked leftovers go into the cooler first. Wrap raw meat well and keep it at the bottom so its juices cannot drip onto anything else. The USDA warns that bread or salad greens touched by raw meat juices should be thrown out.

A cooler thermometer helps here too. The CDC says to check temperatures of food kept in coolers and to throw out anything that has thawed or gone above 40°F.

Winter outages and the snow myth

It is tempting to put the shopping outside when there is snow on the ground. The USDA advises against it, because outdoor temperatures vary, the sun can warm food and animals can reach it. Its suggestion is smarter. Fill buckets, empty milk containers or cans with water, leave them outside to freeze, then bring that homemade ice indoors for the fridge, freezer or cooler.

What to throw out and what to keep

When power returns, go through the fridge one item at a time. The table below summarises the FoodSafety.gov chart for refrigerated food that has been at 40°F (4°C) or above for more than 2 hours.

Food	Verdict
Raw or cooked meat, poultry, fish and seafood	Throw out
Lunch meat, hot dogs, bacon and sausage	Throw out
Milk, cream, yogurt and sour cream	Throw out
Soft cheeses such as Brie, mozzarella, ricotta and cottage cheese	Throw out
Shredded and low fat cheeses	Throw out
Hard cheeses such as Cheddar, Swiss and Parmesan	Keep
Processed cheeses	Keep
Fresh eggs and egg dishes	Throw out
Butter and margarine	Keep
Cut fresh fruit and vegetables	Throw out
Whole fresh fruit and vegetables	Keep
Cooked pasta, rice and potatoes	Throw out
Pizza, casseroles, soups and stews	Throw out
Bread, rolls, muffins and tortillas	Keep
Mustard, ketchup, jam, pickles and olives	Keep
Opened creamy dressings	Throw out
Opened vinegar based dressings	Keep
Opened mayonnaise, tartar sauce and horseradish	Throw out if above 50°F (10°C) for more than 8 hours
Opened baby formula	Throw out

The USDA adds a few foods worth calling out. Garlic stored in oil, custard and cream pies, cream filled pastries and batters and doughs should all be discarded after more than 4 hours without power. High acid foods like mustard, ketchup and relish are fine to keep, although they may spoil sooner than usual.

Whatever the chart says, the agencies agree on one rule. If any food has an unusual smell, colour or texture, throw it out. The opposite is not true, though. The CDC warns that unsafe food can make you sick even if it looks and smells normal, so a sniff test never proves anything is safe.

Frozen food after an outage

Frozen food is more forgiving. FoodSafety.gov says food may be safely refrozen if it still contains ice crystals or is at 40°F (4°C) or below, although its quality may suffer. The USDA notes that food in the front of the freezer, in the door or in small thin packages defrosts faster than large, thick items at the back or bottom, so check those first.

Frozen food	Still has ice crystals	Above 40°F for more than 2 hours
Meat, poultry and seafood	Refreeze	Throw out
Soups and stews	Refreeze	Throw out
Ice cream and frozen yogurt	Throw out	Throw out
Hard cheeses	Refreeze	Refreeze
Bread, rolls and plain cakes	Refreeze	Refreeze
Frozen meals and pizza	Refreeze	Throw out
Packaged vegetables	Refreeze	Throw out after 6 hours above 40°F

Expect softer vegetables and some loss of texture in milk and soft cheeses that have been refrozen. That is a quality problem rather than a safety one.

How to make the cold last longer

Most of the best tricks happen before the power goes out. These come straight from the USDA and CDC advice.

1. Keep the freezer full. The USDA suggests filling empty space with frozen jugs of water, bags of ice or gel packs. A full freezer lasts roughly twice as long as a half full one.
2. Group food together. Packed items keep each other cold.
3. Freeze what you do not need right away. If a storm is forecast, the USDA suggests freezing leftovers, milk and fresh meat you will not use soon so they stay cold longer.
4. Have a cooler and gel packs ready. The CDC lists them as part of basic outage preparation.
5. Keep thermometers in both appliances. Check that the fridge is at 40°F or below and the freezer at 0°F or below on an ordinary day too.

Our power outage preparation checklist puts these steps alongside water, lighting and medical needs so you can prepare everything in one go.

Keeping the fridge running with backup power

The surest way to avoid losing food is to keep the fridge powered. A fridge does not run all the time. Its compressor cycles on and off, so its average draw is far lower than the short surge it needs to start. That makes it one of the more realistic loads for a portable power station or generator.

How long a battery will last depends on your particular fridge and station. Our refrigerator runtime calculator works it out from your fridge’s running watts or energy label and shows the station size needed for a full 24 hours. For a broader view of what a typical station can handle, see how long a power station lasts.

You do not have to run the fridge nonstop. Because a closed fridge holds its temperature for hours, some households power it for a spell, then switch the station to other loads, watching the thermometer to make sure it stays at or below 40°F. If you charge your station away from home, our guide on charging a power station from a car covers how slow that route is.

If you use a generator, run it outdoors only, well away from doors, windows and vents. The CDC is clear that generators must never run inside a home or garage because of carbon monoxide. Our generator size calculator helps you check that a fridge and your other essentials fit within its rating, and our guide to home backup power options compares batteries, generators and standby systems.

Medicines that need refrigeration

Some medicines, including insulin, need to stay cool. Do not rely on the food rules for these. Check the label or leaflet, and ask your pharmacist or doctor what to do if a refrigerated medicine has been without power. If someone in your home depends on powered medical equipment, our guides to CPAP backup power and oxygen concentrator backup cover planning for those needs.

Cleaning the fridge afterwards

If spoiled food leaves a smell, the USDA suggests removing shelves and drawers and washing them in hot water and detergent, then rinsing with a sanitising solution of 1 tablespoon of unscented liquid chlorine bleach per gallon of drinking water. Wash the inside with hot water and baking soda, rinse with the same solution and leave the door open for about 15 minutes. For stubborn smells it suggests a wipe with equal parts vinegar and water, or a dish of fresh coffee grounds or baking soda left in the fridge.

One firm rule applies after flooding. The USDA says a refrigerator or freezer that has been submerged by floodwater, even partly, is unsafe to use and must be thrown away.

The bottom line

Keep the doors shut, know your 4 hour and 48 hour limits, and let a thermometer make the call once those times have passed. Move high risk food into a cooler with ice if the outage drags on, and throw out anything perishable that has spent more than 2 hours above 40°F. A little preparation, such as a full freezer, two cheap thermometers and a plan for backup power, can save a fridge full of food the next time the grid goes down.

Frequently asked questions

How long can food stay in the fridge without power?

Up to 4 hours if the door stays closed. The USDA, CDC and FoodSafety.gov all use the same figure. After 4 hours, move perishable food into a cooler with ice or frozen gel packs, or plan to throw it out.

How long will a freezer keep food frozen without power?

A full freezer holds a safe temperature for about 48 hours and a half full freezer for about 24 hours, as long as the door stays closed. Small, thin packages and food in the door thaw faster than large items at the back.

Can I refreeze food that thawed during a power cut?

Yes, if it still contains ice crystals or has stayed at 40°F (4°C) or below. FoodSafety.gov says it can be refrozen safely, although the texture and flavour may suffer. Ice cream and frozen yogurt that have thawed should be thrown out.

Is milk safe after a power outage?

Not if it has been above 40°F (4°C) for more than 2 hours. FoodSafety.gov lists milk, cream, yogurt and soft cheeses among the foods to discard after that point, while butter, hard cheeses and processed cheeses can usually be kept.

Can I put food outside in the snow during a winter outage?

The USDA advises against it. Outdoor temperatures change through the day, sunshine can warm food quickly and animals can get to it. A better idea is to fill buckets or empty milk jugs with water, let them freeze outside and use that ice in the fridge or a cooler.

Can a portable power station keep my fridge running?

Often yes, for a while. A fridge cycles on and off, so its average draw is much lower than its starting surge. How many hours you get depends on the fridge and the station, which our refrigerator runtime calculator works out from your own numbers.