Short answer: An unopened refrigerator keeps perishable food safely cold for about 4 hours without power. Keep the door closed. If the outage will last longer, move perishable food to an insulated cooler with ice or frozen gel packs and keep it at 40°F (4°C) or below. If you cannot keep it cold, discard the refrigerated perishables.
A freezer is different: a full freezer generally keeps food safe for about 48 hours, and a half-full freezer for about 24 hours, provided the door stays closed. These are approximate food-safety guidelines—not guarantees for every refrigerator or freezer.
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What to do immediately when the power goes out
- Note the time the power failed. The outage clock matters, especially if you later need to decide whether refrigerated food exceeded the safe window.
- Keep the refrigerator and freezer doors closed. Do not open them just to inspect the food. Every opening releases cold air and shortens the period the appliance can retain a safe temperature.
- Do not add warm food. Warm food raises the temperature inside the refrigerator or cooler and uses up the available cold.
- Prepare a cold-storage plan. Get an insulated cooler, ice, frozen gel packs, or—if the outage will be prolonged and you know how to handle it safely—dry ice.
- Use a thermometer if you have one. Check the refrigerator or freezer as briefly as possible. An appliance thermometer or food thermometer is more useful than a numbered refrigerator control setting or your hand.
- Plan to separate raw meat, poultry, and seafood from ready-to-eat food if you move anything. Keep raw items sealed so leaking juices cannot contaminate other food.
The USDA emergency food guidance recommends keeping appliance doors closed and having a cooler and ice ready when an outage may continue.
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The two temperature clocks you need to understand
Power-outage advice is often reduced to one sentence—“a refrigerator lasts four hours”—but there are really two related clocks:
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- The outage clock: An unopened refrigerator is generally expected to keep perishable food safe for about four hours without power.
- The temperature-exposure clock: Perishable food that has been above 40°F for more than two hours should generally be discarded.
The four-hour figure is the conservative default when you do not have reliable temperature evidence. It is not a physical guarantee that every refrigerator will stay below 40°F for exactly four hours. A refrigerator that was already warm, was opened repeatedly, sits in a very hot room, or has a damaged door seal may become unsafe sooner.
Conversely, a trustworthy temperature reading can provide better evidence than elapsed time. Refrigerated perishable food that can be confirmed to have remained at 40°F or below may generally be kept. If you do not know how warm it became or how long it stayed warm, do not use smell, taste, or appearance to fill in the missing information.
Refrigerator versus freezer: how long each lasts
| Compartment or condition | Approximate period with the door closed | What it means |
|---|---|---|
| Fresh-food refrigerator compartment | About 4 hours | After that, transfer perishables to a cooler at 40°F or below, or discard them if no cold source is available. |
| Full standalone freezer | About 48 hours | Frozen contents provide thermal mass, but the door must remain closed. |
| Half-full standalone freezer | About 24 hours | A less-full freezer warms sooner because it contains less frozen material. |
| Freezer compartment inside a refrigerator | May be less than 24 or 48 hours | Do not automatically apply the full-freezer estimate to a small refrigerator freezer. |
These figures come from FoodSafety.gov’s power-outage chart and related FDA guidance. They assume the door remains closed and the appliance was operating normally before the outage. A full freezer lasts longer because its frozen contents slow warming; that does not make a full refrigerator’s fresh-food compartment safe for 48 hours.
What happens at the four-hour mark?
If the power is still off after about four hours, move refrigerated perishables to an insulated cooler. Pack the food with enough ice or frozen gel packs to keep it at 40°F or below, keep the cooler closed, and add more ice as it melts. A food thermometer can verify whether the cooler is actually cold enough.
Use a separate cooler for raw meat, poultry, and seafood if possible. Otherwise, keep those foods sealed and physically separated from ready-to-eat foods. Put leaking packages in a second bag or leakproof container.
If you have no ice, gel packs, powered cooler, or other reliable cold source, discard refrigerated perishable food once the applicable safe period has passed. Do not leave the refrigerator open while deciding what to move; make the decision and remove food efficiently.
Which refrigerator foods should be discarded?
After the refrigerator has been without power for about four hours without a cold source, the safest household default is to discard high-risk perishables. This includes:
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- Milk, cream, sour cream, buttermilk, yogurt, and soy milk
- Fresh shell eggs, egg dishes, and egg products
- Leftovers, casseroles, soups, stews, gravy, stuffing, and cooked rice, pasta, or potatoes
- Meat, tuna, chicken, shrimp, and egg salads
- Cut fruit and vegetables, pre-washed greens, cooked vegetables, tofu, and opened vegetable juice
- Soft cheeses, shredded cheese, cream-filled pastries, custards, cheesecake, quiche, and cream-based desserts
- Opened spaghetti sauce, creamy dressings, fish sauce, oyster sauce, and refrigerated dough products
Some foods commonly remain safe longer because they are less perishable or are shelf-stable. Subject to contamination and the specific product, these often include:
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- Butter and margarine
- Hard cheeses such as cheddar, Swiss, Parmesan, provolone, and Romano
- Processed cheese
- Whole, uncut fruits and vegetables
- Bread, rolls, bagels, tortillas, muffins, and cakes without perishable fillings
- Peanut butter, jelly, mustard, ketchup, pickles, olives, soy sauce, barbecue sauce, and similar condiments
- Unopened shelf-stable foods
This is not an exhaustive list. For food-by-food decisions, use the complete FoodSafety.gov refrigerated-food outage chart. When in doubt about a high-risk perishable, throwing it away is safer than trying to rescue it.
What if the food still feels cold?
Your hand cannot measure a safe food temperature accurately. “Still cold” is not a precise temperature, and food can contain harmful bacteria even when it looks, smells, and tastes normal.
Use a thermometer where possible:
- Refrigerator: Keep at 40°F (4°C) or below.
- Freezer: Keep at 0°F (-18°C) or below.
- Above 40°F for more than two hours: Discard perishable food.
A freestanding appliance thermometer is especially useful because many refrigerator controls show a setting number rather than the actual internal temperature. See the FDA guidance on refrigerator thermometers and FoodSafety.gov’s four food-safety steps.
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How to handle frozen food after an outage
When power returns, inspect individual frozen packages rather than assuming everything in the freezer is safe or unsafe. Frozen food may generally be refrozen or cooked if:
- Ice crystals remain in the food; or
- The food is confirmed to be at 40°F or below and has not been above that temperature for more than two hours.
Refreezing may reduce texture and flavor, particularly in foods with high water content. Ice cream and frozen yogurt should generally be discarded after they thaw because their quality and texture deteriorate significantly, even where other frozen foods may safely be refrozen.
Discard frozen perishables that were above 40°F for more than two hours. The USDA’s freezing and food-safety guidance explains the ice-crystal and temperature rules in more detail.
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Ways to preserve food during a long outage
Cooler with ordinary ice
For most households, a cooler with ice or frozen gel packs is the simplest and safest option. Transfer only the foods that need refrigeration, pack ice around them, keep raw foods sealed and separated, and check the cooler with a thermometer. Open it only when necessary.
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You can make ice outdoors in cold weather and use it in a cooler or appliance, but do not use snow or outdoor air as an uncontrolled food-storage system. Outdoor temperatures fluctuate, sunlight can warm food even when the air is below freezing, and food can be contaminated by animals, dirt, floodwater, or other unsanitary conditions.
Dry ice
Dry ice can extend freezer storage, but it is not a casual substitute for ordinary ice. USDA says approximately 50 pounds of dry ice can keep an 18-cubic-foot full freezer cold for about two days. The actual result depends on the freezer, its contents, the packaging, and how it is used.
Dry ice requires all of the following precautions:
- Never touch it with bare hands; it can cause severe frostbite.
- Do not place it in direct contact with food.
- Use it only in a well-ventilated area.
- Never put it in an airtight container. As it sublimates, carbon dioxide gas can create dangerous pressure.
- Keep people and pets away from accumulated carbon dioxide. The gas can build up in an enclosed space and create an asphyxiation hazard.
For detailed handling information, see the USDA emergency guidance, CDC dry-ice safety information, and FDA dry-ice safety guidance. Ordinary ice in a cooler is usually the better household choice.
Generator
A generator can power a refrigerator, but there is no universal generator size or runtime that is safe to promise without the refrigerator’s model information. Check the refrigerator’s rating plate and manual for running and startup power requirements, account for every other appliance connected to the generator, and follow both manufacturers’ instructions.
Fuel-burning portable generators must be operated outdoors and at least 20 feet from doors, windows, and vents, with exhaust directed away from the home. Never run one in a house, garage, basement, shed, carport, or any partly enclosed area. Use a battery-operated or battery-backup carbon-monoxide detector inside the home. The CDC generator-safety guidance and CPSC warning explain the carbon-monoxide risk.
Battery power station
A battery power station may run a refrigerator for a period of time, but runtime depends on the battery’s usable capacity, inverter output, refrigerator startup surge, ambient temperature, and other loads. Check that the power station can handle the refrigerator’s startup and running requirements, and use the refrigerator and power-station manufacturers’ instructions. Do not assume a particular battery size will run every refrigerator for the same length of time.
Move food elsewhere
If a neighbor, friend, community food locker, or other suitable freezer has dependable power, moving food there may be more practical than trying to power the refrigerator. Transport food in a cooler and keep it at 40°F or below during the move. Do not combine questionable food with food that has been safely frozen.
What to do when power returns
- Check temperatures before eating questionable food. Do not use smell or taste as the test.
- Inspect frozen packages. Look for ice crystals or verify that food is at 40°F or below.
- Discard food that exceeded the applicable limit. A refrigerator cooling again does not make previously unsafe food safe.
- Clean leaks and spoiled food promptly. Wash contaminated surfaces according to the appliance manufacturer’s cleaning instructions.
- Let the refrigerator return to its normal operating temperature before restocking it with new groceries.
A refrigerator may not restart instantly after a brief power interruption. Some compressors delay restarting while the refrigeration system equalizes pressure; this can be an automatic protective behavior rather than a failure. A short outage does not automatically mean you need to unplug and reset the appliance.
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If it does not cool, check the outlet, breaker, power cord, controls, and any display alerts. Consult the model manual before attempting a reset. Brand-specific troubleshooting is available from GE Appliances and LG. If the appliance still does not cool, move food to a cooler or another working refrigerator and arrange service.
Can a refrigerator remain unplugged for weeks or months?
Yes—if it is empty and stored correctly. The appliance itself does not have a universal maximum time it can remain switched off. The food-safety concern during an outage is usually the food inside, not damage caused simply by the refrigerator being off.
For long-term storage:
- Remove all food.
- Clean the interior and dry it thoroughly.
- Disconnect the ice maker and water supply where applicable, following the model instructions.
- Leave the doors slightly open or otherwise ventilated to prevent mold and odors. Do not store it closed while damp.
- Follow the manufacturer’s vacation or storage instructions.
Whirlpool’s storage guidance and LG’s long-term storage guidance both emphasize removing food, cleaning, drying, and ventilating the appliance.
If the refrigerator was moved on its side, follow the manufacturer’s required upright settling period before reconnecting it. For example, LG currently recommends at least two hours for units moved on their side, but the instructions for your particular model take priority. See LG’s moving guidance.
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Medication, infant formula, breast milk, and vaccines
Do not apply the ordinary food chart automatically to medicine or other temperature-sensitive products. Follow the product label, manufacturer’s storage instructions, or advice from a pharmacist or clinician. Some medicines lose potency after improper storage without showing any visible change. The CDC power-outage guidance recommends checking medication instructions and replacing affected medicine as soon as possible after a prolonged outage.
Opened infant formula is among the products listed for discard after unsafe temperature exposure. Breast milk, vaccines, and specialized nutrition products can have product-specific rules, so contact the manufacturer or an appropriate health professional rather than relying on the general 4-hour refrigerator rule. FDA information on refrigerated medical products is available here.
Floodwater, stormwater, fire, smoke, or chemicals
Temperature is not the only safety issue. Discard food that touched floodwater or stormwater. Food in porous, non-waterproof, cardboard, or screw-top packaging may be unsafe after flooding. Smoke, fire, and fire-extinguishing chemicals can contaminate food even if the refrigerator stayed cold.
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A practical decision checklist
- Less than four hours, door closed: Perishables are generally expected to remain safe if the refrigerator was operating normally before the outage. Keep the door closed.
- About four hours, power still off: Transfer perishables to a cooler with ice or gel packs and verify 40°F or below. Without a cold source, discard them.
- More than four hours, but reliable temperature evidence shows 40°F or below: Food may generally be kept, subject to the product and contamination risks.
- Food was above 40°F for more than two hours: Discard perishable food.
- Full freezer: Use about 48 hours as the approximate closed-door guideline.
- Half-full freezer: Use about 24 hours as the approximate closed-door guideline.
- Ice crystals remain: Frozen food may generally be refrozen or cooked, although quality may decline.
- Flood, smoke, fire, or chemical exposure: Apply contamination guidance even if the temperature stayed low.
Frequently Asked Questions
Is food safe after six hours if the refrigerator door stayed closed?
Not by the ordinary time-based rule. After about four hours without a cold source, discard refrigerated perishables unless reliable temperature evidence shows they remained at 40°F or below. Do not use smell, appearance, or taste as proof of safety.
What if the milk is still cold?
Feeling cold is not precise enough. Check the milk or refrigerator with a thermometer if possible. If the milk may have been above 40°F for more than two hours, discard it.
Can I eat eggs after a power outage?
Fresh shell eggs are perishable. If the refrigerator was without power for about four hours and there was no cold source or reliable temperature history, discard them. Use the complete FoodSafety.gov outage chart for product-specific guidance.
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Generally yes if ice crystals remain or the meat is confirmed to be at 40°F or below. Expect some loss of texture or quality. Discard it if it was above 40°F for more than two hours.
Can I put food outside in the snow?
It is not recommended as a general food-storage method. Outdoor temperatures fluctuate, sunlight can warm food, and animals, dirt, or floodwater can contaminate it. Use ice made outdoors in a cooler instead.
How long does a refrigerator freezer last without power?
A small freezer compartment inside a refrigerator may last less than the standard estimates. The approximate 48-hour figure is for a full standalone freezer, and 24 hours is for a half-full standalone freezer, with the door closed.
Is dry ice safe to use in a refrigerator?
Dry ice requires careful handling. Never touch it bare-handed, place it directly against food, seal it in an airtight container, or use it in an area where carbon dioxide can accumulate. Ordinary ice in a cooler is usually simpler and safer.
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Can I run the refrigerator from a generator?
Yes, if the generator can handle the refrigerator’s startup and running requirements and is used correctly. Operate a fuel-burning generator outdoors at least 20 feet from doors, windows, and vents—never in a garage, house, basement, shed, or carport—and use carbon-monoxide detection indoors.
Will unplugging the refrigerator damage it?
An empty refrigerator can remain unplugged for an extended period when it is cleaned, dried, and ventilated. Leave the doors slightly open to prevent mold and odors, and follow the manufacturer’s storage instructions.
What should I do if the refrigerator does not cool after power returns?
Check the outlet, breaker, controls, power cord, and display alerts. Some compressors delay restarting briefly after an interruption. If cooling does not resume, move food to a cooler or another working refrigerator and consult the model manual or arrange service.
The Bottom Line
Keep the refrigerator closed and use four hours as the conservative default for refrigerated perishables. At that point, move food to a cooler with ice and keep it at 40°F or below—or discard it. A full freezer is a separate case and generally lasts about 48 hours, while a half-full freezer lasts about 24 hours. When in doubt, trust a thermometer and the official food-safety guidance, not smell, taste, or guesswork.
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