How to Keep Food Safe During a Power Outage

When the power goes out, the clock starts on everything in your refrigerator and freezer. Knowing the official time limits and having a thermometer inside each appliance lets you save what is safe and confidently throw out what is not.

Every rule below comes from FoodSafety.gov (which publishes USDA's outage chart), CDC and Ready.gov. Product picks are research-based from manufacturer specs; we do not test products.

The core time rules

FoodSafety.gov: "your refrigerator will keep food safe for up to 4 hours during a power outage. Keep the door closed as much as possible."

FoodSafety.gov: "A full freezer will hold a safe temperature for approximately 48 hours (24 hours if it is half full and the door remains closed)."

• Refrigerator: up to 4 hours with the door closed
• Full freezer: about 48 hours; half-full: about 24 hours, door closed
• Discard refrigerated perishables (meat, poultry, fish, eggs, leftovers) after 4 hours without power
• Discard perishables held at 40°F or above for more than 2 hours

Before the outage: set yourself up

• Put an appliance thermometer in the fridge and the freezer. Fridge should be at or below 40°F, freezer at or below 0°F (CDC).
• Keep the freezer full: frozen water bottles fill gaps and later become drinking water or cooler ice.
• Know where to get ice, and have a cooler and frozen gel packs ready.

During the outage

Keep doors shut. Every opening lets cold air out. CDC says that if the power has been out for 4 hours, move perishable food into a cooler with ice or frozen gel packs to keep it at 40°F or below. Plan meals around the fridge first, then the freezer, then shelf-stable food.

After power returns: keep, refreeze or toss

FoodSafety.gov: "Food may be safely refrozen if it still contains ice crystals or is at 40°F (4°C) or below, however, its quality may suffer." Check the appliance thermometer, then check each item. Never taste food to decide whether it is safe.

Medicines in the fridge

Ready.gov: "If the power is out for more than a day, discard any medication that should be refrigerated, unless the drug's label says otherwise." Insulin has specific FDA guidance; see our first aid and medical prep guide.

Eat in the right order

A simple meal plan stretches what you can safely use. In the first hours, eat perishable food from the refrigerator: leftovers, dairy and opened items. Next, use food from the freezer, which stays colder longer as long as the door stays shut. Save canned and shelf-stable food for later in the outage, when the fridge and freezer are no longer safe.

Write down the time the power went out. When you are tired and cold it is easy to lose track of hours, and the time rules only work if you know when the clock started. A note on the fridge door and a quick thermometer check every few hours removes the guesswork.

Make your cooler work harder

• Pre-chill the cooler with ice before loading it
• Pack the most perishable items (meat, poultry, fish, dairy) at the bottom, closest to the ice
• Fill empty space with ice or frozen water bottles; air warms faster than ice
• Keep the cooler in the coolest, shadiest spot in the house and open it as little as possible
• Put an appliance thermometer inside the cooler too, and keep it at 40°F or below

Research-based picks: tools that help

Cheap thermometers do most of the work; a high-capacity cooler buys time. Specs from manufacturer pages, checked October 27, 2026.

Food safety outage checklist

• Thermometer in fridge and freezer
• Freezer kept full; frozen water bottles in gaps
• Cooler and gel packs ready
• Doors closed; note the time the power went out
• After 4 hours, move perishables to a cooler at 40°F or below
• Refreeze only items with ice crystals or at 40°F or below
• When in doubt, throw it out

Keeping the fridge running

A fridge is one of the most common reasons people buy backup power. Sizing a power station or generator to keep it running depends on your model and outage length; the backup power calculator walks through it.