The clock starts the second the power drops.
Refrigerated food held above 40°F for more than 4 cumulative hours should be discarded — that's roughly how long it takes bacteria to reach unsafe levels. Keeping the door closed is what buys you that time: an unopened fridge holds about 4 hours, a full freezer about 48 hours, a half-full freezer about 24 hours. When in doubt, throw it out — never taste-test questionable food to check whether it's still safe.
How long you actually have
| Appliance | Time held safely (door closed) |
|---|---|
| Refrigerator | ~4 hours |
| Full freezer | ~48 hours |
| Half-full freezer | ~24 hours |
Every door opening lets cold air escape and shortens these windows. If you know an outage is coming, group items and open the door as little as possible, or move critical items to a cooler with ice.
Eating order
- Perishables first — refrigerated meat, dairy, and leftovers, within the 4-hour window.
- Freezer contents next — as they thaw, within the 24–48 hour window depending on how full the freezer was.
- Shelf-stable and canned goods — no clock, but rotate stock so nothing expires unused.
- Long-term storage last — rice, beans, freeze-dried staples. Save these for when the shorter-dated food is gone.
Caloric planning
Plan for roughly 1,500–2,000 kcal per day for a sedentary adult sheltering in place; more if you're doing physical labor, exposed to cold, or the situation extends past a few days. Underfeeding to stretch supplies further degrades judgment and physical capacity right when you need both.
Frequently asked questions
What is the 4-hour fridge rule?
Perishable refrigerated food held above 40°F (4°C) for more than 4 cumulative hours should be discarded, since that is roughly how long it takes bacteria to multiply to unsafe levels at room temperature. Keeping the door closed is what buys you that time.
How long does a closed fridge or freezer stay cold during an outage?
An unopened refrigerator holds a safe temperature for about 4 hours. A full freezer holds for about 48 hours, and a half-full freezer for about 24 hours. Every door opening lets cold air out and shortens that window.
What order should I eat food in during a power outage?
Perishables first, within their safe window. Then shelf-stable and canned goods. Long-term storage staples like rice, beans, and freeze-dried food come last, since they don't depend on the clock.
Building out longer-term stores? See Grid-Down Food Storage for canning, root cellars, and rotation.
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