Power cuts
Preparing for a power cut
How to get ready for a power cut in the UK, what to do when the lights go out, how to keep food and people safe, and when to call 105.
Food & water · Free tool
Power cut: is my food still safe?
A live countdown for your fridge and freezer during a power cut, based on Food Standards Agency time limits, with what to do now and when the power comes back.
Last reviewed
How to use it (4 steps)
- Tap when the power went off, or enter the date and time.
- Say whether you have a fridge, how full your freezer is, and whether the doors have been opened.
- Watch the countdown and follow "What to do now". It is saved on this device, so you can close the page and come back.
- When the power comes back, tap "It's back now" and read the advice for that moment. Clear the countdown when you are done.
Loading the countdown…
The method, in detail
How the countdown works
The tool starts a clock from the moment you say the power went off. It compares the time without power against the Food Standards Agency’s time limits for a fridge and freezer with the door kept shut.
| Appliance | Window with the door shut |
|---|---|
| Fridge | 4 hours |
| Full freezer | 48 hours |
| Half-full freezer | 24 hours |
Each card shows how much of the window has gone, when it ends, and a status:
- Within the window: the official time has not run out yet.
- Act soon: less than an hour is left, or the door has been opened a lot.
- Window passed: the official time has run out while the power was off.
If the power comes back within the window, the tool says so. The Food Standards Agency says a cut of less than 4 hours is unlikely to affect the safety of chilled or frozen food.
The countdown is saved on this device, in the same place as your progress. It keeps going if you close the page or your phone goes to sleep, because it works from the time the power went off, not a running timer. Tap Clear the countdown to delete it.
Why the door doesn’t change the clock
Opening the door lets warm air in. The Food Standards Agency says that frequent opening may raise the temperature, but it gives no figure for how much each opening costs. We will not make one up. So the countdown stays the same, the card turns amber and the tool asks you to check with a thermometer. Chilled food needs to stay below 8°C.
What the tool will never do
It will never say your food is safe. A time window is an estimate. A warm kitchen, a fridge that was already full of warm food, or a faulty seal can all shorten it. Use the countdown to decide when to act, not as permission to eat something you are unsure about.
Where the figures come from
Every figure on this page was checked against these official pages on 25 October 2026.
- 4 hours (fridge), 48 hours (full freezer), 24 hours (half-full freezer), below 8°C, eat in order, under 4 hours unlikely to affect safety, steaming hot: Food Standards Agency, Food safety in a power cut: advice for consumers. Food Standards Scotland gives the same figures in Food safety during a power cut.
- Fridge 0 to 5°C, freezer about -18°C, freezing cooked food once: Food Standards Agency, How to chill, freeze and defrost food safely.
- Refreezing with ice crystals or at 4°C (40°F) or below, “when in doubt, throw it out”: US Centers for Disease Control and Prevention, Keep Food Safe After a Disaster or Emergency. We use it only because the UK pages do not give a refreezing figure.
- 105: Power Cut 105, the free number for England, Scotland and Wales.
Sources
- Food Standards Agency (GOV.UK), Food safety in a power cut: advice for consumers.
- Food Standards Agency (GOV.UK), How to chill, freeze and defrost food safely.
- Food Standards Scotland, Food safety during a power cut.
- US CDC, Keep Food Safe After a Disaster or Emergency.
Frequently asked questions
How long does food last in the fridge during a power cut?
The Food Standards Agency says your fridge should stay cold for up to 4 hours if you keep the door shut. After 4 hours without power, throw away food that needs to be kept in the fridge, unless the power came back within that time.
How long will my freezer keep food frozen?
The Food Standards Agency estimates up to 48 hours for a full freezer and 24 hours for a half-full one, with the door kept shut. These are estimates, so check the food before you use it.
Can I refreeze food that has started to thaw?
The UK guidance does not give a figure. US CDC guidance says you can refreeze or cook thawed food that still has ice crystals or is at 4°C (40°F) or colder. Thawed food that you cook can be frozen again once, and reheated only once after that.
Does opening the fridge door shorten the time?
It can. The Food Standards Agency says frequent opening lets room-temperature air in and can warm the fridge. No official source gives a figure for how much, so the countdown does not change. It warns you instead and suggests checking with a fridge thermometer.
Who do I call about a power cut?
Call 105, free, in England, Scotland and Wales, to report a power cut or get updates. If there is danger to life, such as fallen power lines, call 999.
Does this tool tell me my food is safe?
No. It tells you whether the official time window has passed. Food can go off sooner, for example on a hot day or if the door was opened. If in doubt, throw it out.
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