How long does food last in the fridge without power?

A fridge keeps food safely cold for up to 4 hours in a power cut if you keep the door shut, according to the Food Standards Agency (checked 29 Aug 2026). A full freezer keeps food frozen for up to 48 hours, a half-full one for about 24 hours.

The slightly longer answer

The Food Standards Agency’s power cut guidance (checked 29 Aug 2026) says a fridge should stay cold for up to 4 hours, and that food in your freezer should stay frozen for up to 48 hours if the freezer is full, or about 24 hours if it is half full. Both figures assume the doors stay shut.

The FSA notes these are estimates: timings vary with the make and model, how warm the room is, and how often the doors are opened. The same guidance says a power cut of under 4 hours is unlikely to affect the safety of chilled or frozen food at all, which covers the vast majority of UK power cuts. So the winning move in the first hours is to do nothing except keep the doors closed.

In a longer cut, the number that matters is 8°C. The FSA says food can be kept in a fridge at temperatures under 8°C during a power cut, but once it reaches 8°C or above, food that normally needs refrigerating should be eaten within 4 hours. Eat food in this order: chilled food first, then any defrosted frozen food that does not need cooking, then perishables kept at room temperature such as bread, and tins and dried food last. If it is genuinely cold outside, below 8°C, the FSA says you can store food out there, kept clean, dry, out of direct sunlight and protected from animals.

When the cut outlasts those windows, be ruthless. Looks and smell are not a safety test, so anything that has fully defrosted or sat above 8°C for more than 4 hours goes in the bin: if in doubt, do not eat it. The wider plan for the lights going out is in the power cut guide, and there are tricks for stretching these hours in keeping the fridge cold in a power cut.

Should I open the fridge to check how cold it is?

No. Every opening lets the cold out, and the FSA timings assume the doors stay shut. If you have a fridge thermometer you can read quickly, use it; otherwise leave the door closed and go by the clock: 4 hours for the fridge, 48 or 24 for the freezer.

What should I eat first when the power is off?

The FSA’s order: chilled food that normally lives in the fridge first, then defrosted frozen food that does not need cooking, then room-temperature perishables like bread, and tins, bottles and dried food last. Your freezer is effectively a slow-release larder for the day, so eat towards it.

Can I refreeze food that has started to defrost?

The FSA’s power cut guidance is silent on refreezing. Its chilling and freezing guidance says you can “freeze food again once cooked”, but “you’ll only be able to reheat it once after that”, and that fully defrosted food should be used “within 24 hours”. So the route is cook it, then eat it or freeze the cooked dish.

Does putting food outside work in winter?

Yes, with conditions. The FSA says that if the weather is below 8°C you can store food outside, in clean, dry conditions, out of direct sunlight and protected from animals (checked 29 Aug 2026). A sealed box in a shaded spot does it. It is a winter trick only; check the actual temperature.

What about medicines that live in the fridge?

Medicines such as insulin have their own storage rules, and this page’s food timings do not apply to them. Ring your pharmacy or NHS 111 before using or throwing away any refrigerated medicine after a power cut, rather than guessing either way.

Sources & review

Food safety in a power cut, Food Standards Agency on GOV.UK: the 4-hour fridge figure, 48 and 24-hour freezer figures, the 8°C rule and outdoor storage conditions. The page says nothing about refreezing. Checked 29 August 2026.
Power cuts, Food Standards Scotland: the same timings and the order in which to eat food. Checked 29 August 2026.
How to chill, freeze and defrost food safely, Food Standards Agency on GOV.UK: freezing food again once cooked, reheating only once after that, and using fully defrosted food within 24 hours. Checked 29 August 2026.

Neither FSA page gives a rule for refreezing raw food that thawed in a power cut, so we have not invented one; the page says what the guidance does cover and stops there. Reviewed by: TBC. Review date: 29 August 2026.