Power Outage Food Safety Calculator
Enter what was in the refrigerator or freezer, how long the power was out, and any temperature evidence you have. The calculator applies federal outage guidance and shows the rule behind the result.
Food safety decisionKeep
- Recommended action
- Keep the food if it has no spoilage or contamination signs; the closed-refrigerator outage time is within the federal four-hour limit.
- Estimated unopened hold time
- 4
- Estimated time margin
- 1
- Maximum time above 40°F
- 2
- Rule applied
- Refrigerator-duration rule for a closed refrigerator.
Elapsed-time hold estimates assume the refrigerator or freezer door stayed closed.
Never taste food to decide whether it is safe.
How to use this calculator
- Choose whether the food was in a refrigerator or freezer when the outage began.
- Choose the closest food group from the federal outage charts.
- Enter the outage length and whether the appliance door stayed closed.
- Use thermometer records or visible ice crystals when you have reliable evidence.
- Read the decision, the rule applied, and the remaining time margin.
How the decision is calculated
Federal power-outage guidance starts with a few time limits. A closed refrigerator is expected to keep food cold for about 4 hours. A closed full freezer is expected to hold safe temperatures for about 48 hours, while a half-full freezer is expected to hold them for about 24 hours. This calculator uses the half-full value when freezer fullness is unknown.
The elapsed-time calculation is:
hold time = 4 refrigerator hours, 48 full-freezer hours, or 24 half-freezer hours
time margin = max(0, hold time − outage hours)
For perishable food that has been above 40°F, the warm-time limit is normally 2 hours. If the surrounding temperature is above 90°F, the limit drops to 1 hour. The calculator uses that limit when thermometer records establish how long the food was above 40°F.
How temperature evidence changes the result
Reliable temperature evidence is stronger than an elapsed-time estimate. If refrigerated perishable food stayed at 40°F or below, the result is keep. If known time above 40°F exceeds the applicable warm-time limit, the result is discard. If the time above 40°F is exactly at the limit, the result is kept at the boundary with an instruction to use it immediately.
For frozen food, visible ice crystals or a reliable 40°F-or-below reading supports a cook-or-refreeze decision. Without that evidence, the freezer hold time is only an estimate. If the freezer door was opened, or the outage exceeded the estimated hold time, the calculator returns an indeterminate result and recommends discarding unless temperature history can establish safety.
What moves the result most
The biggest drivers are food group, temperature evidence, door status, and freezer fullness. Foods such as meat, milk, eggs, soft cheese, cooked leftovers, and cut produce are treated more conservatively than chart-listed foods such as hard cheese, butter, and uncut produce. A full freezer receives a longer unopened hold estimate than a half-full freezer because the frozen mass warms more slowly.
What this calculator leaves out
This tool does not inspect the food and does not model bacterial growth. It also does not cover floodwater, smoke, chemical exposure, damaged packaging, cross-contamination, or local health-department instructions. Smell and appearance are not reliable safety tests, and tasting food is never a safe way to decide.
Worked example
Suppose milk and leftovers were in a closed refrigerator during a 5 hour outage, with no reliable thermometer history. The refrigerator hold time is 4 hours, so the time margin is max(0, 4 − 5) = 0 hours. Because the food is perishable and the closed-refrigerator estimate has been exceeded, the result is indeterminate with a conservative discard recommendation.
If a full freezer was out for 50 hours but the food still had ice crystals, the elapsed-time margin is max(0, 48 − 50) = 0 hours. The decision is cook or refreeze because the ice-crystal rule is stronger evidence than the elapsed-time estimate.
Common questions
How long does a refrigerator stay cold without power?
Federal guidance uses about 4 hours for a refrigerator if the door stays closed. Once that closed-door estimate is exceeded, perishable refrigerated food needs reliable temperature history to avoid a conservative discard recommendation.
How long does a full or half-full freezer stay cold?
A full unopened freezer is expected to hold safe temperatures for about 48 hours. A half-full freezer is expected to hold them for about 24 hours, and this calculator uses 24 hours when fullness is unknown.
Can food with ice crystals be refrozen?
Yes, federal guidance says frozen food that still contains ice crystals may be refrozen or cooked. Check packages for damage or contamination, and discard anything exposed to floodwater, smoke, chemicals, or cross-contamination.
Which refrigerated foods are most likely to be discarded after four hours?
Meat, poultry, seafood, milk, eggs, soft cheese, cooked leftovers, and cut produce are treated as perishable foods. If they were in a refrigerator without power for more than 4 hours and you do not have reliable temperature evidence, the conservative action is to discard them.
Why does 90°F change the two-hour rule?
Federal food-safety guidance shortens the room-temperature limit for perishable food when the surrounding temperature is above 90°F. In that condition, this calculator uses 1 hour above 40°F instead of 2 hours.
Can smell or appearance show whether food is safe?
No. Food can contain unsafe bacteria without smelling or looking spoiled. Do not taste food to check it; use time, temperature evidence, and contamination history instead.