Freezer frosting up?

A door left ajar or a worn gasket is the usual cause, because warm room air brings moisture that freezes into frost. If the door is fine, a frost-free model's defrost system may have failed, or a manual-defrost freezer simply needs defrosting.

Not sure which one it is? Snap your freezer and we’ll narrow it down.

Is the freezer actually warm, not just frosty?

Food that isn't staying frozen is a different symptom. Freezer not freezing

Likely causes

Door left ajar or a worn gasket
Most commonModerate DIY
Frost is heaviest near the door and along the gasket, which may be torn, stiff or gapped. A shelf item can also hold the door open a crack.
Part: $50–440 (gasket replacement)
Frequent or long door openings
CommonEasy DIY
Frost is spread evenly through the freezer, and the door seals fine. Each opening lets in humid air that freezes on the coldest surfaces. Hot food put in uncovered adds moisture too.
Defrost heater, timer or thermostat failure
CommonCall a pro
On a frost-free model, a thick sheet of frost or ice on the back panel, and temperature that drifts up over days. A manual defrost clears it for a while, then it comes back.
Part: $100–440 (defrost system repair)
Manual-defrost freezer needs defrosting
CommonEasy DIY
A chest or older upright freezer with no automatic defrost builds frost on the walls by design. Defrost it when the frost is about a quarter inch thick.
Humid location or an overfull freezer
Less commonEasy DIY
A freezer in a humid garage or basement, or one packed so tight air can't circulate, frosts faster. See freezer not freezing if food is also staying soft.

Quick checks

Unplug the freezer before defrosting. Never chip ice with a knife or any sharp tool; it can puncture the refrigerant line. Don't use a heat gun or open flame to speed up a defrost. Refrigerant work is for a certified pro only. Keep the food in a cooler while it defrosts, and food that has thawed shouldn't be refrozen without checking.

Make sure nothing is holding the door open, and that it latches firmly.
Close the door on a dollar bill and try to pull it out, at several spots. If it slides out easily, the gasket isn't sealing there.
Note where the frost is: along the door edge points to the gasket, and the back panel points to the defrost system.
Cover food and let hot food cool before it goes in, and open the door less often.
If it's a manual-defrost model, defrost it: unplug it, move the food to coolers, leave the door open, and put towels down for the melt water.

Sharpen the read

Diagnose your freezer in seconds, for free

No account, no phone number. Fixology’s AI reads your photo and tells you what’s likely wrong, how worried to be, and whether it’s a DIY fix.

Snap one of these:

the frost or ice inside, showing where it builds up
the door gasket, especially any gaps or tears
the model label inside the door

Add a note or more photos next. Nobody calls you.

When to call a pro

Frost comes back within days of a defrost on a frost-free model, the back panel is solid ice, or the gasket is torn and you'd rather not replace it yourself. For a freezer that's also warm, see freezer not freezing. If the fridge side is warm while the freezer is cold, see fridge warm but freezer cold. For lifespan and upkeep, see the freezer guide.

Typical cost: HomeAdvisor puts stand-alone freezer repair at $90–650. A service call runs $150–200, and a diagnostic of $60–100 is often credited toward the repair.

Sources: HomeAdvisor: How much does refrigerator repair cost? (updated June 19, 2026)

After a scan, Fixology can also help you find pros near you.