What is the best temperature for a refrigerator and freezer?

Getting your refrigerator and freezer temperatures right is a balancing act between keeping food safe and not wasting energy. While there are official guidelines, the numbers on your temperature dial aren't always a perfect reflection of the actual temperature inside.

The Official Food Safety Guidelines

The U.S. Food and Drug Administration (FDA) has clear recommendations based on slowing the growth of harmful bacteria:

• Refrigerator: Set to 40°F (4°C) or below.
• Freezer: Set to 0°F (-18°C).

At 40°F, bacterial growth slows dramatically. At 0°F, it stops, and frozen food is preserved safely for an extended time (though its quality may decline over many months).

Why Your Dial Setting Might Be Wrong

The dial in your fridge—whether it's a 1-9 scale or shows actual temperatures—controls a thermostat, not a thermometer. It tells the appliance when to turn the cooling system on and off. The actual temperature inside can vary depending on a few factors:

• How full it is: An empty fridge warms up faster when you open the door. A full one holds its temperature better, but poor airflow can create warm spots.
• How often you open it: Frequent door-opening lets cold air out, forcing the system to work harder to maintain temperature.
• Where it's located: A fridge in a hot garage or in direct sunlight will have to run more often than one in a cool kitchen.

How to Check the Real Temperature

The best way to know for sure is to use an inexpensive appliance thermometer. Don't trust the built-in display without verifying it first.

For the refrigerator, place the thermometer in a glass of water in the center of a middle shelf and leave it for at least 5-8 hours. For the freezer, place it between a few frozen items. If the reading is too high, adjust the dial one notch colder, wait another 5-8 hours, and check again. If you find your milk is slushy or your lettuce is freezing, you've gone a bit too far.

The Bottom Line: Safety and Savings

Once you've confirmed your fridge is at or below the 40°F mark, there's no safety benefit to making it colder. Setting it much colder just uses more electricity and increases your energy bill. A few minutes with a thermometer can save you from spoiled food and wasted money.