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Pumped breast milk keeps well when it is stored the right way. These times are from the CDC for healthy, full-term babies. If your baby was born early or is in the hospital, follow your care team’s advice, which may be stricter.
Breast milk storage chart
| Type of breast milk | Room temperature (77 F / 25 C or colder) | Fridge (40 F / 4 C) | Freezer (0 F / -18 C or colder) |
|---|---|---|---|
| Freshly expressed | Up to 4 hours | Up to 4 days | Within 6 months is best, up to 12 months is acceptable |
| Thawed (was frozen) | Within 2 hours | Up to 1 day (24 hours), counted from fully thawed | Never refreeze |
| Left over from a feed | Use within 2 hours after the baby finishes, then throw away |
An insulated cooler bag with frozen ice packs keeps fresh milk for up to 24 hours, for example when you travel or work.
Storing tips
- Wash your hands before pumping or handling milk.
- Use clean, food-grade containers with tight lids, or bags made for breast milk.
- Label every container with the date you pumped it. Use the oldest milk first.
- Store milk in small amounts, about 2 to 4 ounces (60 to 120 mL), to avoid waste.
- Keep milk at the back of the fridge or freezer, not in the door, where the temperature changes more.
- Leave about an inch of space at the top of containers you freeze, since milk expands.
How to thaw breast milk
- Thaw in the fridge overnight, or
- Hold the container under lukewarm running water, or set it in a bowl of warm water.
- Never thaw or warm breast milk in the microwave. It heats unevenly and creates hot spots that can burn your baby’s mouth.
- Use thawed milk within 24 hours if kept in the fridge (counted from when it is fully thawed), or within 2 hours once it is at room temperature or warmed.
How to warm it
Breast milk does not need to be warm; many babies drink it cool or at room temperature. If your baby prefers it warm, set the sealed container in a bowl of warm water for a few minutes, swirl gently (do not shake hard), and test a few drops on your wrist. It should feel warm, not hot.
Does it look or smell different?
Stored breast milk separates into a creamy layer on top. That is normal: swirl it to mix. Some thawed milk smells soapy or metallic because of a natural enzyme (lipase). Most babies still drink it. If your baby refuses it, talk to a lactation consultant.
Not sure how much to put in each bottle? Try the breast milk calculator.