How Long Does Breast Milk Last?
Last updated
Freshly pumped breast milk keeps for up to 4 hours at room temperature, up to 4 days in the refrigerator, and about 6 months in the freezer, though up to 12 months is acceptable, according to the US CDC. 1 The CDC says milk thawed in the refrigerator should be used within 24 hours. 1
Key takeaways
- The CDC says freshly expressed or pumped milk can be kept at room temperature (77°F or colder) for up to 4 hours. 1
- In the refrigerator, the CDC allows freshly pumped milk for up to 4 days. 1
- In the freezer, the CDC says about 6 months is best, and up to 12 months is acceptable. 1
- Milk thawed in the refrigerator should be used within 24 hours - counted from when it is completely thawed, not from when it left the freezer. 1
- Leftover milk from a feeding should be used within 2 hours, then discarded. 1
- The CDC says thawed breast milk should never be refrozen. 1
**A quick, honest note:** we're not medical professionals - everything here was researched by us from the public sources listed at the bottom of this page, and it isn't professional advice. Read our full note ↓
Breast milk storage times at a glance
| Where you store it | How long the CDC says it keeps |
|---|---|
| Room temperature (77°F or colder) | Up to 4 hours |
| Refrigerator | Up to 4 days |
| Freezer | About 6 months is best; up to 12 months is acceptable |
Source: US CDC. 1
How long does breast milk last in the fridge?
Freshly expressed or pumped breast milk lasts up to 4 days in the refrigerator, according to the US CDC. 1 The CDC's storage guidance states: "Freshly expressed or pumped milk can be stored: At room temperature (77°F or colder) for up to 4 hours. In the refrigerator for up to 4 days. In the freezer for about 6 months is best; up to 12 months is acceptable." 1
How long can breast milk sit out at room temperature?
Freshly pumped breast milk can sit at room temperature for up to 4 hours, provided the room is 77°F or colder, according to the US CDC. 1 This 4-hour window applies to milk that has just been expressed - not to milk that was previously frozen and thawed, which the CDC treats differently. 1
How long does breast milk last in the freezer?
Frozen breast milk keeps for about 6 months at best quality, and up to 12 months is still acceptable, according to the US CDC. 1 The CDC frames 6 months as the preferred window rather than a hard expiry, with 12 months as the outer limit. 1
How long is thawed breast milk good for?
Breast milk thawed in the refrigerator should be used within 24 hours, and the US CDC is specific about when that clock starts. 1 The CDC states: "If you thaw breast milk in the refrigerator, use it within 24 hours. Start counting the 24 hours when the breast milk is completely thawed, not from the time when you took it out of the freezer. Once breast milk is brought to room temperature or warmed, use it within 2 hours." 1
That last point matters: once thawed milk has been warmed or brought to room temperature, the CDC's window shortens to 2 hours. 1
Can you reuse breast milk left over from a feeding?
Breast milk left in the bottle after a feeding should be used within 2 hours and then discarded, according to the US CDC. 1 The CDC states: "If your baby did not finish the bottle, use the leftover milk within 2 hours. After 2 hours, leftover breast milk should be discarded." 1
Can you refreeze breast milk?
No. The US CDC's guidance is unambiguous: "Never refreeze breast milk after it has thawed." 1
Can you warm breast milk in the microwave?
The US CDC says breast milk should never be thawed or heated in a microwave, because microwaving can destroy nutrients and create hot spots that can burn a baby's mouth. 1 The CDC instead describes thawing milk in the refrigerator overnight, in warm or lukewarm water, or under lukewarm running water, and advises washing hands well before expressing or handling breast milk. 1
Frequently asked questions
How long does breast milk last in the fridge?
Up to 4 days for freshly expressed or pumped milk, according to the US CDC. 1
How long can breast milk sit out?
Up to 4 hours at room temperature (77°F or colder) if freshly pumped, according to the US CDC. 1
How long is thawed breast milk good for?
Within 24 hours if thawed in the refrigerator, counted from when it is completely thawed; within 2 hours once warmed or brought to room temperature, according to the US CDC. 1
Can leftover breast milk from a bottle be reused?
The US CDC says to use it within 2 hours, then discard it. 1
Can thawed breast milk be refrozen?
No - the US CDC says never to refreeze breast milk after it has thawed. 1
A note from us
We're the team behind Yael & Michal. We are not doctors, nurses, lactation consultants, or psychologists, and nothing here is professional advice.
Everything above was researched by us from public, reputable sources - we name and link every one of them below - and summarized as carefully as we could, as a free resource for other mothers. We do this because we wished something like it had existed for us.
We try hard to get it right, and we cite our sources so you can check us. But we are not a medical authority, and this cannot replace talking to a professional who knows you and your baby. Please check anything that matters with your doctor, midwife, or an IBCLC lactation consultant.
If something feels urgent, contact your healthcare provider or emergency services.
Read our full Medical Disclaimer · How we research and write
Sources
- US CDC. https://www.cdc.gov/breastfeeding/breast-milk-preparation-and-storage/handling-breastmilk.html (retrieved 2026-07-10).