In short
- With the door closed, the fridge keeps food safe for about 4 hours. A full freezer lasts about 48 hours; a half-full one, about 24.
- During the outage, open the fridge and freezer as little as possible.
- When power returns, throw out meat, fish, eggs, milk and leftovers that spent more than 2 hours above 40 °F (4 °C).
- Never taste food to check whether it’s safe: when in doubt, throw it out.
How long your fridge and freezer last without power
Official guidance from the United States (the Department of Agriculture, USDA, and FoodSafety.gov) and from Scotland (Food Standards Scotland) gives the same figures, always with the door kept closed:
| Appliance | Keeps food safe for |
|---|---|
| Fridge | Up to about 4 hours |
| Full freezer | About 48 hours |
| Half-full freezer | About 24 hours |
The Scottish guidance warns these are estimates: they depend on the make and model of the fridge and on how warm your home is.
Before an outage: what to have ready
If the power goes out often where you live, the USDA recommends:
- Keeping a thermometer in the fridge and another in the freezer. The fridge should be at 40 °F (4 °C) or below and the freezer at 0 °F (−18 °C) or below.
- Keeping the freezer full: fill gaps with frozen water bottles or bags of ice. Full, it lasts twice as long as half-empty.
- Grouping food together, because it stays cold longer that way.
- Freezing things you won’t need soon, such as leftovers, milk or fresh meat.
- Having an insulated cooler and frozen gel packs.
During the outage
- Keep the fridge and freezer doors closed. Every time you open them, warm air gets in.
- If the outage will last longer than 4 hours, the USDA advises moving fridge food into a cooler with ice, adding ice as it melts so it stays at 40 °F (4 °C) or below.
- In the freezer, food at the front, in the door or in small, thin packs thaws faster than large items at the back.
- For a long outage, the USDA mentions dry ice: 50 pounds (about 23 kg) should keep an 18-cubic-foot (about 510-litre) freezer cold for 2 days. Don’t touch it with bare hands or put it in direct contact with food.
- Food Standards Scotland suggests eating fridge food first, then thawed frozen food, then bread and other perishables that don’t need the fridge, and leaving cans, jars and dry food for last.
When power returns: what to throw out from the fridge
FoodSafety.gov’s rule is to throw out perishable food that spent more than 2 hours at 40 °F (4 °C) or above. If you didn’t have a thermometer, go by time: more than 4 hours without power in the fridge. This table summarizes its chart:
| Throw out | Can be kept |
|---|---|
| Meat, poultry, fish and seafood, raw or cooked, and anything that was thawing | Hard cheeses (cheddar, Parmesan, Swiss…) and processed cheese |
| Lunch meats, hot dogs, bacon and sausage | Butter and margarine |
| Milk, cream, yogurt and soy milk | Whole fresh fruit, uncut |
| Eggs and egg dishes; custards and puddings | Whole fresh vegetables, uncut, mushrooms and herbs |
| Soft and fresh cheeses (queso fresco, cottage, mozzarella, ricotta, Brie…), shredded and low-fat cheeses | Mustard, ketchup, pickles, olives, jams, and soy or barbecue sauces |
| Leftovers, casseroles, soups, pizza, and cooked pasta, rice or potatoes | Vinegar-based dressings and opened fruit juices |
| Cut fruit and vegetables, ready-made salads and cooked vegetables | Bread, cakes, tortillas and fruit pies |
| Opened baby formula | Peanut butter, dried fruit and raisins |
Special cases: opened mayonnaise is thrown out if it spent more than 8 hours above 50 °F (10 °C). The USDA adds that you should throw out any food, such as bread or salad greens, that got juice from raw meat or fish on it, and anything with an unusual smell, colour or texture.
When power returns: what to do with frozen food
According to FoodSafety.gov, you can refreeze food that still has ice crystals or is at 40 °F (4 °C) or below, though it may lose some flavour and texture. For food that spent more than 2 hours at 40 °F (4 °C) or above:
- Throw out: meat, poultry and fish; stews and soups; milk; eggs out of the shell; soft and shredded cheeses; frozen meals and pizza; cakes and pastries with custard or cheese filling. Ice cream always goes, even if it still has ice crystals.
- Can be refrozen: bread and cakes without custard, hard cheeses, flour and nuts, and waffles or pancakes. Fruit and fruit juices too, unless they turn mouldy, smell yeasty or feel slimy.
- Frozen vegetables and vegetable juices are thrown out if they spent more than 6 hours above 40 °F (4 °C).
A difference between countries: 40 °F (4 °C) or 46 °F (8 °C)
The guides don’t fully agree on temperature. The U.S. one sets the limit at 40 °F (4 °C). The Scottish one says that during a power cut food can stay in the fridge as long as it doesn’t reach 8 °C (46 °F), and that if it does, fridge food should be eaten within 4 hours. We follow the more cautious limit, 40 °F (4 °C). The Scottish guidance also asks for extra care with people at higher risk of food poisoning.
How to keep your fridge running during an outage
If outages are frequent, a battery or portable power station can keep the fridge going. A 200 W fridge-freezer, which according to the official table from Argentina’s energy regulator (ENRE) runs about half the time, uses about 200 × 0.45 × 8 = 720 Wh in an 8-hour outage. When it starts, the motor briefly draws a lot more than that, and the inverter has to handle it. Work out your numbers with our power outage battery calculator and see which inverter you need.
Cooking without power
Food Standards Scotland points out you can cook on a gas cooker, a camping stove or a barbecue, following the manufacturer’s instructions, and that a barbecue must never be used indoors. Cooking this way is slower than usual: make sure food is steaming hot all the way through. If there’s no running water, clean your hands with alcohol-based sanitiser.
Sources and references
- FoodSafety.gov (U.S. Government), last reviewed August 8, 2024. Food Safety During Power Outage.
- USDA Food Safety and Inspection Service. Keep Your Food Safe During Emergencies: Power Outages, Floods & Fires.
- Food Standards Scotland (Scottish Government). Food safety during a power cut.
- Ente Nacional Regulador del Gas y la Electricidad (Argentina). Consumo básico de electrodomésticos (fridge wattage and share of time running, in Spanish).
Frequently asked questions
How many hours does food last in the fridge without power?
About 4 hours if you keep the door closed, according to the U.S. Department of Agriculture and Food Standards Scotland. A full freezer lasts about 48 hours, and a half-full one about 24.
Can I refreeze food that thawed during a power outage?
Yes, if it still has ice crystals or is at 40 °F (4 °C) or below, though it may lose flavour and texture. If it spent more than 2 hours at 40 °F (4 °C) or above, meat, fish, stews and frozen meals must be thrown out. Ice cream always goes.
How do I know if food is still safe after a power outage?
With a fridge thermometer: if it reads 40 °F (4 °C) or below, the food is safe. Never taste it to find out: every official guide insists on this. When in doubt, throw it out.
