This is the question everyone searches mid-outage, usually while standing in front of an open fridge trying to decide whether to trust their eyes and nose. Here are the actual USDA-backed time limits, plus how to make the call with confidence.
The core numbers
| Appliance | Safe time (door closed) | Notes |
|---|---|---|
| Refrigerator | About 4 hours | Keep the door closed as much as possible |
| Full freezer | About 48 hours | A full freezer holds cold far longer than a half-empty one |
| Half-full freezer | About 24 hours | Consolidate food into fewer containers if you know an outage is coming |
The rule that actually matters: 40°F and 4 hours
The USDA's safety threshold is simple: perishable food held above 40°F (4°C) for more than 4 hours total should be discarded, even if it looks and smells fine. Bacteria that cause foodborne illness don't always change the appearance, smell or taste of food — "it still looks okay" is not a reliable safety test.
How to actually check, not guess
- Keep an appliance thermometer in the fridge and freezer year-round — this turns "how long has it been" into a direct, reliable reading instead of a guess.
- Freezer: if it still has ice crystals and is at or below 40°F, it's safe to refreeze or cook. If it's above 40°F for more than 2 hours, discard meat, poultry, seafood and leftovers.
- Fridge: if the power was out more than 4 hours, discard perishables — meat, poultry, fish, eggs, milk, soft cheeses, leftovers, and anything with cut fruit or vegetables. Hard cheese, butter, and unopened condiments are generally more forgiving.
- When genuinely in doubt, throw it out — the cost of replacing food is always lower than the cost of foodborne illness.
Keeping food safe longer without grid power
A full fridge/freezer with the door kept shut is the free option. Beyond that, a portable power station sized to your fridge's running and starting watts (150W running, up to 1,200W starting for a typical full-size unit) can keep it running continuously through a multi-day outage — run your fridge model through our free calculator to see exactly what size covers it, and for how many hours.