Every figure on this page comes from USDA and FoodSafety.gov guidance and none is ours. This is the one page in this cluster where a number invented to be helpful could make somebody ill, so nothing here is estimated, rounded or filled in.
The four figures that answer the question:
- The refrigerator keeps food safe for up to 4 hours during a power outage, with the door kept closed as much as possible. After 4 hours without power, discard refrigerated perishable food such as meat, poultry, fish, eggs and leftovers.
- A full freezer holds a safe temperature for approximately 48 hours, and 24 hours if it is half full, with the door kept closed.
- The threshold is 40 °F. Food may be safely refrozen if it still contains ice crystals or is at 40 °F or below, though its quality may suffer.
- The normal settings are 40 °F or below for the refrigerator and 0 °F or below for the freezer.
And one rule that is not a number: never taste food to determine its safety.
Before it happens: the thermometer
USDA's guidance is to keep an appliance thermometer in both the refrigerator and the freezer, so that you can tell whether food is still safe after a power outage.
That is the whole preparation, and it is why this page belongs on a maintenance site rather than an emergency one. Without a thermometer you are guessing about the one variable that matters, and the guidance itself is built around knowing the temperature rather than knowing the elapsed time.
A second, free version: keep the freezer full. A full freezer holds temperature for roughly twice as long as a half-full one on USDA's own figures, and containers of water fill space for nothing.
During: keep the doors closed
The 4-hour and 48-hour figures both assume the door stays shut. USDA's guidance says so explicitly, and every time the door opens the clock effectively resets downward.
Which means the instinct to check on things is the thing that costs you the food. Decide before the power goes what you will need, take it out in one go if you must, and then leave it alone.
After: the two questions, in order
Question one: what is the temperature now?
Read the thermometers. That reading, not the number of hours, is what USDA's guidance is built around, and the refreezing rule is stated in terms of ice crystals or 40 °F or below rather than in terms of elapsed time.
Question two: how long was it out?
If you have no thermometer reading, the hour figures are what you have. Four hours for the refrigerator. Approximately 48 for a full freezer, 24 for a half-full one.
Where the two answers conflict, the temperature is the more direct measure, and where you have neither, USDA's guidance still holds: do not taste it.
The rule that catches people out
Never taste food to determine its safety. USDA states it plainly and it is the single most important sentence on this page.
The reason it needs saying is that the alternative feels reasonable. Food that has been warm can look normal, smell normal and taste normal. Sight and smell are not the test, and neither is a small sample.
Refreezing, which is a quality question and a safety one at once
USDA's guidance is that food may be safely refrozen if it still contains ice crystals or is at 40 °F or below, however its quality may suffer.
Two distinct points in one sentence. The safety condition is ice crystals or 40 °F or below. The quality caveat is separate and is not a safety statement.
So a freezer that stayed cold enough is a different situation from one that did not, and looking for ice crystals is a real check rather than a comforting one.
What to do with the appliance afterwards
Once the food question is settled, the appliance question follows.
Check the temperature is coming back down. If the refrigerator is not returning to 40 °F or below, that is a fault rather than a lingering effect of the outage, and there is an ordered set of checks for it that starts with the door seal and the vents rather than with a repair.
Check the drain and the base, because a period of warming and re-cooling often produces more condensate than usual, and standing water under the drawers has its own cause and fix.
Clean before you restock. Anything that leaked or thawed in the compartment is a cleaning job, and doing it while the fridge is empty is the only easy time. The general routine is in how to deep clean a kitchen.
What this page will not do
It will not give you a figure for a partially working appliance. USDA's figures are for a refrigerator and freezer without power. A fridge that is running but warm is a different situation and no published hour figure covers it. The thermometer reading is what you have.
It will not tell you a food is fine. It gives you the published thresholds and the published instruction, and the decision is yours with those in front of you.
It will not give you a cooler or dry ice figure. Those exist in the same USDA guidance and this article did not open and read that section, so it does not quote it. If you are planning for a long outage, go to FoodSafety.gov directly rather than to a summary.
FAQ
How long is food safe in the fridge without power? USDA guidance is up to 4 hours with the door kept closed as much as possible, and to discard refrigerated perishable food such as meat, poultry, fish, eggs and leftovers after 4 hours without power.
How long does a freezer stay safe? Approximately 48 hours for a full freezer, and 24 hours if it is half full, with the door remaining closed.
Can I refreeze food that thawed? USDA's guidance is that food may be safely refrozen if it still contains ice crystals or is at 40 °F or below, though its quality may suffer.
Can I tell by smell or taste whether it is still good? No. USDA's guidance is explicit: never taste food to determine its safety.
What temperature should the fridge and freezer be normally? 40 °F or below for the refrigerator and 0 °F or below for the freezer, with an appliance thermometer in each.
What if I do not have a thermometer? Then the hour figures are what you have, and they assume the doors stayed closed. Buying an appliance thermometer before the next outage is the whole of the preparation this page recommends.
Sources: USDA and FoodSafety.gov guidance on food safety during a power outage and on refrigeration, read 2026-08-28, for all four figures quoted here: up to 4 hours for the refrigerator, approximately 48 hours for a full freezer and 24 for a half-full one, the 40 °F refrigerator and 0 °F freezer settings, the refreezing condition of ice crystals or 40 °F or below, the appliance thermometer recommendation and the instruction never to taste food to determine its safety.
One disclosure the map's flag requires. Our fetcher received an HTTP 403 from both foodsafety.gov and fsis.usda.gov on 2026-08-28, so the figures above are reported from those agencies' own indexed guidance rather than from a page we opened and read line by line, and they are labeled as such rather than presented as verbatim quotations. That is our retrieval failing, not anything on the agencies' side. Because this is the food safety row and the map requires every hour and temperature figure to be quoted verbatim from FoodSafety.gov or USDA, this page should not publish until somebody with working access has opened those pages and confirmed each figure directly. Nothing here is estimated, and no figure has been added, rounded or inferred.
