Power Outage Food Safety Calculator
Find out how long fridge and freezer food stays safe during a power outage.
Know exactly what to keep and what to discard for each type of stored food.
The Danger Zone for food is 40°F to 140°F (4°C to 60°C). Bacteria multiply fast in that range, doubling roughly every 20 minutes at body temperature. That is the whole reason the four-hour figure exists: it is not about when food starts to spoil, it is about how long a population of bacteria takes to reach a dose that makes you ill.
How long appliances stay safe:
| Appliance | Keep Closed | How Long Food Stays Safe |
|---|---|---|
| Refrigerator | Yes | Up to 4 hours |
| Chest freezer (full) | Yes | 48 hours (2 days) |
| Chest freezer (half full) | Yes | 24 hours |
| Upright freezer (full) | Yes | 48 hours |
| Upright freezer (half full) | Yes | 24 hours |
The single most important rule: Keep the doors closed. Every time you open the refrigerator during a power outage, cold air escapes and the safe time window shortens.
Refrigerator food safety by outage length:
| Outage Duration | Status |
|---|---|
| 0–2 hours | All food safe, no action needed |
| 2–4 hours | Food likely still safe if door stayed closed |
| 4+ hours | Discard all perishables (meat, dairy, leftovers, eggs, etc.) |
Foods that MUST be discarded after 4 hours:
- Raw or cooked meat, poultry, seafood
- Milk, cream, soft cheese, yogurt, sour cream
- Cooked pasta, rice, potatoes, casseroles
- Mayonnaise, tartar sauce, hollandaise
- Opened cream-based sauces and soups
- Custards, puddings, cheesecake, mousse
- Fresh-cut fruits and vegetables
- Pies with meat, egg, or custard filling
Foods that are SAFE even after extended outage (pantry-stable):
- Unopened peanut butter, jelly, jam
- Hard and processed cheeses (not sliced)
- Fruit juices
- Canned goods (intact, not bulging)
- Bread, rolls, cakes, muffins, tortillas
- Butter and margarine
- Fresh uncut fruit and vegetables
- Vinegar-based dressings and condiments
- Dried herbs and spices
Frozen food rules:
Ice crystals still present and the food refrigerator-cold, below 40°F (4°C), means it is safe to refreeze. Thawed completely and above 40°F for two hours or more means do not refreeze. Cook it now or bin it.
Refreezing costs you texture, not safety. Ice crystals rupture cell walls, so a refrozen steak will be softer and will weep when it thaws again. That is a quality problem and nothing more.
“When in doubt, throw it out.” Food that has sat in the danger zone can look, smell and taste completely normal. Spoilage bacteria are the ones that announce themselves; the pathogens that put people in hospital generally do not.
Buy a freezer thermometer. It costs a few dollars and it answers the whole question after the fact, because it records the highest temperature reached while you were out of the house. Without one, a family returning from a weekend away has no way to tell a four-hour outage from a thirty-hour one.
Keeping food cold longer:
- Add bags of ice or dry ice to the refrigerator
- Move refrigerator items to a cooler with ice
- A full freezer stays cold longer than a half-empty one
- Freeze water bottles ahead of hurricane/storm season to use as cooling blocks
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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