How Long Food Lasts in the Fridge and Freezer in an Outage
How long food lasts in the fridge and freezer during a power outage: the FDA and USDA 4-hour rule, 48-hour freezer rule, and a keep-or-toss chart.
When the power goes out, the most expensive thing in your kitchen is suddenly on a timer, and nobody hands you the clock. A fridge full of groceries can run a few hundred dollars, but the real question isn’t what it cost. It’s whether the food inside is still safe to eat once the lights come back, and the answer depends almost entirely on the temperature and how long it stayed there. The federal agencies that govern food safety have already done the math, and their rules are simple to follow.
This guide turns the FDA, USDA, and FoodSafety.gov power-outage rules into one keep-or-toss decision tree. We didn’t test, taste, or measure anything ourselves. Everything below is the agencies’ guidance as of June 2026, restated and organized so you can act on it in the dark with a flashlight in your teeth. We’ll flag the few places where rules tighten in a heat wave and point you to the primary sources at the bottom. One phrase shows up across every one of these agencies, and it’s worth keeping in your head the whole time: when in doubt, throw it out.
How long does food stay safe in the fridge without power?
A closed refrigerator keeps food safe for about 4 hours after the power fails. The FDA, USDA Food Safety and Inspection Service, and CDC all give the same number, and they all attach the same condition: the door has to stay shut.
Those 4 hours aren’t a countdown to spoilage for every item. It’s the window in which the air inside stays at a safe temperature, defined as 40F or below. Each time you open the door, warm room air rushes in and cold air falls out, and the clock effectively speeds up. The CDC and FoodSafety.gov are blunt about it: keep the refrigerator door closed as much as possible to hold the cold.
Once the refrigerator has been without power for more than 4 hours, the agencies say to discard perishable foods. FoodSafety.gov and the CDC list these explicitly as meat, poultry, fish, eggs, milk, and leftovers, along with cut fruits and vegetables. Those are the items bacteria multiply in fastest, and they’re the ones the 4-hour rule is really written to protect. If the outage looks like it’ll run long, the USDA recommends moving those perishables into a cooler packed with ice or frozen gel packs and keeping that cooler at 40F or below. That buys you more time without gambling on the fridge.
How long does a full vs half-full freezer hold?
A full freezer holds a safe temperature for about 48 hours after the power goes out; a half-full freezer holds for about 24 hours. In both cases, FoodSafety.gov, the FDA, and the CDC all add the same non-negotiable condition: the door stays closed.
A full freezer lasts twice as long because of mass. A tightly packed freezer is full of already-frozen food acting as one giant ice block, and all that frozen mass has to absorb a lot of heat before anything thaws. A half-empty freezer has less of that thermal ballast, so it warms up roughly twice as fast. It’s also why a smart pre-outage move, covered further down, is to fill the empty space with frozen water jugs so a half-full freezer behaves more like a full one.
Two practical notes the agencies stress. Don’t open the freezer to look; every peek costs you cold air you can’t get back until power returns. And the 48-hour and 24-hour figures are guidelines for a closed, properly working freezer, not guarantees. When power returns, you still check the actual temperature and the food itself before deciding, which is what the next sections cover.
Does a heat wave change the timeline?
Yes. Heat shortens every clock that involves food sitting out of refrigeration. The standard rule from the FDA and USDA is that perishable food shouldn’t be left at room temperature for more than 2 hours, but that drops to 1 hour when the temperature is above 90F.
This matters during an outage for two reasons. Many outages hit during summer storms or heat waves, exactly when your kitchen is hottest and your fridge has no help. And the moment you start pulling food out, staging it on a counter, or transferring it to a cooler, that food is no longer in refrigeration and the 2-hour (or 1-hour) room-temperature clock starts ticking on it. The USDA frames the underlying science as the Danger Zone: bacteria grow most rapidly between 40F and 140F, and the hotter the room, the faster they multiply.
So in a heat wave, treat the timeline as tighter than the headline numbers. The fridge’s 4-hour rule assumes the appliance stays sealed and cold. Once food is exposed to a 90-plus-degree room, you’ve got about an hour before it should be discarded. If your home is sweltering, that’s a strong argument for prioritizing cold over comfort, which is the cross-link theme we return to at the end: when battery or generator power is scarce, the fridge usually earns its watts before the air conditioner does.
How do I actually tell if it is still safe?
Use a thermometer, not your senses. The FDA’s clearest single instruction is to keep an inexpensive appliance thermometer in both the refrigerator and the freezer, so that when power returns you can read the actual temperature instead of guessing. The threshold to remember is 40F.
Here’s the decision the agencies lay out. If the refrigerator stayed at 40F or below, the food is safe. For the freezer, if food still contains ice crystals or reads 40F or below on a thermometer, FoodSafety.gov and the FDA say it’s safe to refreeze or to cook, though refreezing may cost you some quality. If perishable food has been above 40F for more than 2 hours (or more than 1 hour above 90F), discard it.
Two rules sit above all of this. First, never taste food to decide whether it’s safe. The CDC and USDA are emphatic that food can look, smell, and taste normal and still carry enough bacteria or toxins to make you sick. Tasting tests nothing except your luck. Second, when in doubt, throw it out. If you can’t confirm a food stayed cold enough for long enough, the agencies want you to discard it rather than risk it. An appliance thermometer is cheap. A foodborne illness is not.
Keep-or-toss by food type: a quick decision table
Not everything in your fridge plays by the same rules. Highly perishable, protein-rich, and moist foods are the ones that turn dangerous fast and have to go after 4 hours above 40F. High-acid, high-fat, and shelf-stable items are far more forgiving and can usually be held. The table below merges the FDA, USDA, and FoodSafety.gov power-outage charts into one keep-or-toss verdict by category, for a refrigerator that has been above 40F for 4 or more hours. Treat it as a guide, not a guarantee; the agencies want you to evaluate each item separately.
| Food category | Examples | Verdict above 40F for 4+ hours |
|---|---|---|
| Meat, poultry, seafood | Raw or cooked beef, chicken, fish, lunch meat, hot dogs | Discard |
| Eggs and egg dishes | Fresh eggs, egg substitutes, custards, quiche | Discard |
| Milk and soft dairy | Milk, cream, yogurt, soft cheeses, shredded cheese | Discard |
| Leftovers and casseroles | Cooked pasta, rice, soups, stews, pizza, gravy | Discard |
| Cut produce | Cut fruit, cut melon, pre-washed bagged greens, fresh salsa | Discard |
| Opened creamy condiments | Opened mayonnaise, tartar sauce, creamy dressings | Discard if above 50F for 8+ hours |
| Hard cheeses | Cheddar, Parmesan, Romano, processed cheeses | Keep |
| Butter and margarine | Butter, margarine | Keep |
| High-acid condiments | Ketchup, mustard, relish, pickles, jam, jelly, peanut butter | Keep |
| Whole fresh produce | Uncut fruits and vegetables, fresh herbs | Keep |
| Breads and baked goods | Bread, rolls, muffins, bagels (no cream filling or cheese) | Keep |
The pattern is worth learning because it generalizes. Anything moist and protein-rich gets discarded; anything acidic, fatty, or dry tends to survive. The one footnote is opened creamy condiments like mayonnaise: FoodSafety.gov treats those as keepable unless they sat above 50F for more than 8 hours, at which point they go. The table is still a guide, not a guarantee; the agencies want you to evaluate each item and lean on when in doubt, throw it out.
What can I do before and during an outage to buy time?
The most effective moves are the ones you make before the power fails. The agencies’ advice clusters into a short list, and all of it is about adding cold mass and keeping cold air where it belongs.
Before an outage, freeze containers of water and stock up on gel packs so you have a cold reserve ready to move into the fridge or a cooler. Fill empty freezer space with those frozen water jugs so a half-full freezer behaves more like a full one and holds longer. Group food together in both the fridge and freezer, because a tight cluster of cold items insulates itself and warms more slowly than scattered ones. Get an appliance thermometer in place ahead of time so you can read the temperature the moment power returns. And know where to buy dry ice or block ice locally, because that’s your best tool for a long outage.
During the outage, the rules get even simpler. Keep both doors closed as much as humanly possible; this is the single behavior the 4-hour and 48-hour figures depend on. For a long outage, dry ice does the heavy lifting: the FDA states that 50 pounds of dry ice should keep an 18-cubic-foot full freezer cold for about two days. Handle dry ice carefully, with gloves and ventilation, and never touch it bare-handed. If you have backup power but limited capacity, power the refrigerator and freezer before comfort loads. A sealed, cold fridge is one of the cheapest, highest-value things a battery or generator can run, which is exactly why our runtime guides put the fridge ahead of the air conditioner.
Frequently asked questions
How long does food last in the fridge without power?
About 4 hours, according to the FDA, USDA, and CDC, as long as you keep the door closed. After 4 hours, the agencies say to discard perishables such as meat, poultry, seafood, eggs, milk, leftovers, and cut produce. Confirm with FoodSafety.gov, and when in doubt, throw it out.
How long will a freezer keep food frozen during an outage?
A full freezer holds a safe temperature for roughly 48 hours and a half-full freezer for about 24 hours, provided the door stays closed. Filling empty space with frozen water jugs adds cold mass and helps a less-than-full freezer last longer. These figures come from the FDA and FoodSafety.gov.
Can I refreeze food that thawed in a dead freezer?
The FDA and USDA say you can safely refreeze or cook food that still has ice crystals or reads 40F or below on a thermometer. Quality may drop, but it is safe. If it warmed above 40F for more than 2 hours, discard it rather than refreezing.
Is it safe to taste food to check if it spoiled?
No. The CDC and USDA are emphatic that you should never taste food to judge its safety. Spoiled or contaminated food can look, smell, and taste completely normal while still carrying enough bacteria to make you sick. Use a thermometer and the time rules instead, and when in doubt, throw it out.
Does a heat wave change how long food lasts?
Yes. The standard 2-hour limit for perishable food left at room temperature drops to 1 hour when it is above 90F, per the FDA and USDA. Bacteria grow fastest in the 40F to 140F Danger Zone, so hot weather shortens every timeline once food leaves refrigeration.
Should I run my fridge or my AC on backup power first?
Generally the fridge. A sealed, cold refrigerator preserves expensive, perishable food for very little power, while an air conditioner is a comfort load that draws far more. When backup capacity is limited, securing the cold chain first protects your food and your money.
Bottom line
During a power outage, two numbers do most of the work: 4 hours for the refrigerator and about 48 hours for a full freezer, both contingent on keeping the doors closed. After that, lean on the 40F threshold, the ice-crystals-means-refreezable rule, and one habit above all, when in doubt, throw it out. Never taste to test, and always confirm the specifics with the primary sources, because these agency rules can change.
To set yourself up before the next storm, start with our storm power prep checklist and our guide to charging a power station during a storm. And if you’re deciding what your limited backup power should run, read why you power the fridge before the AC, which is the runtime logic behind everything on this page.
This is a living guide; the figures above are from cited FDA, USDA, CDC, and FoodSafety.gov sources as of June 2026, and agency rules can change. Confirm the current guidance with the primary sources linked below before acting, and remember: when in doubt, throw it out.