How Long Does Breast Milk Last in the Fridge?

The fridge is where most pumped milk spends its first hours, whether you’re prepping bottles for daycare or saving an extra pumping session for tomorrow. Knowing exactly how long breast milk lasts in the fridge takes the guesswork out of those 2 a.m. decisions about what to keep and what to toss.

Below you’ll find the current CDC times for fresh, thawed and leftover milk, where the AAP, NHS and ABM differ, plus practical tips to keep refrigerated milk as safe and fresh as possible. These guidelines are for healthy, full-term babies. If your baby is premature or in the hospital, ask your baby’s care team which rules to follow.

Fridge storage times at a glance

Type of breast milk	How long it lasts in the fridge (40°F / 4°C or colder)
Freshly expressed or pumped	Up to 4 days
Thawed in the fridge (previously frozen)	Up to 24 hours, counted from when it is completely thawed
Leftover from a feed	Use within 2 hours after your baby finishes feeding, then discard

These numbers come from the CDC’s breast milk storage guidance, which the CDC adapted from the Academy of Breastfeeding Medicine’s Protocol #8. Other groups differ a little:

Source	Fresh milk in the fridge	Thawed milk	Leftover from a feed
CDC	Up to 4 days; use or throw away after that	Use within 24 hours of fully thawing in the fridge	Within 2 hours after the feed
AAP	Up to 4 days is best (fridge at 39°F or colder); freeze milk you won’t use within 48 to 72 hours	Best within 24 hours; may be used within 48 to 72 hours	Within 2 hours, or if quickly refrigerated, for the next feeding
ABM Protocol #8	4 days optimal; 5 to 8 days only under very clean conditions	Not specified; no recommendation on refreezing	Reasonable to discard within 1 to 2 hours after the feed
NHS (UK)	Up to 8 days at 4°C or lower; use within 3 days if your fridge runs 5 to 10°C or you’re not sure	Use straight away once defrosted	Within 1 hour, then discard

For everyday home use in the US, we follow the CDC’s 4 days, which the AAP also gives. The ABM’s longer time applies only to very clean milk, and the NHS’s 8 days assumes a fridge at 4°C (about 39°F) or lower.

For a quick use-by date on a specific bottle, try our breast milk storage calculator. For the full chart, including room temperature, coolers and freezers, see our main guide to breast milk storage.

Fresh milk: up to 4 days

Freshly pumped or hand-expressed milk can go straight into the fridge and stay there for up to 4 days. Quality is best when you use it sooner, so try to:

• Put milk in the fridge soon after pumping instead of leaving it on the counter.
• Use the oldest refrigerated milk first.
• Freeze milk right away if you don’t expect to use it within 4 days. The CDC says this helps protect the milk’s quality; the AAP advises freezing milk you won’t use within 48 to 72 hours.

La Leche League notes that some nutrients are lost when milk is frozen and suggests giving your baby refrigerated milk before frozen milk whenever possible, so it makes sense to offer refrigerated milk first and keep the frozen stash for backup.

Thawed milk: up to 24 hours

Once frozen milk has thawed in the fridge, the clock changes. The CDC says to use it within 24 hours, counted from the moment it is completely thawed, not from when you took it out of the freezer.

Two more rules apply to thawed milk:

• Never refreeze milk that has fully thawed.
• Once thawed milk is brought to room temperature or warmed, use it within 2 hours (the CDC’s printable chart says 1 to 2 hours).

Our guide on how to thaw frozen breast milk walks you through the safest ways to defrost milk and what to do if milk partly thaws during a power outage.

Leftover milk: don’t put it back

When your baby drinks from a bottle, bacteria from their mouth mix into the milk. That’s why the CDC says leftover milk should be used within 2 hours after your baby finishes feeding and then thrown away. The CDC doesn’t include putting a half-finished bottle back in the fridge. The AAP does say leftover milk can be used for the next feeding if it was quickly refrigerated, and the NHS says to throw it away after 1 hour, so ask your pediatrician if you want to follow a different rule.

To waste less, store and warm milk in smaller portions, about 2 to 4 ounces (60 to 120 ml) at a time, and offer more if your baby is still hungry. Our breast milk intake calculator can help you estimate how much to put in each bottle for your baby’s age and weight.

How to store breast milk in the fridge

Where and how you store milk matters as much as how long.

Keep it at the back, not in the door

The CDC says not to store breast milk in the door of the refrigerator or freezer, because storing it further inside protects it from temperature changes when the door opens and closes. The AAP also recommends the back of the fridge. The CDC says refrigerators should be 40°F (4°C) or below and suggests an inexpensive freestanding appliance thermometer to check.

Use the right containers

• Breast milk storage bags, or clean food-grade glass or plastic containers with tight-fitting lids.
• Not disposable bottle liners or ordinary plastic bags that aren’t meant for breast milk.
• Label each container with the date you expressed the milk. For daycare, add your baby’s name too.

Chill before you combine

You can combine milk from different pumping sessions, but cool the fresh milk in the fridge first. The CDC says mixing freshly expressed milk with already cooled or frozen milk is not advised because it can rewarm the older milk, and that if you combine cooled milk pumped on different days, the storage time is based on when the older milk was first stored.

Keep things clean

Wash your hands before pumping or handling milk, and clean pump parts and bottles after every use. If you pump often, a realistic pumping schedule also helps you rotate milk through the fridge before it reaches the 4-day limit.

Is it normal for fridge milk to look or smell different?

Yes, within limits. Refrigerated milk often separates into a creamy layer on top and a thinner layer below. That’s just the fat rising, and a gentle swirl mixes it back together. Milk can also vary in color from day to day.

Stored milk sometimes develops a soapy or metallic smell. La Leche League says the reasons are not well understood but it may be due to the breakdown of milk fats over time, and that if the milk was stored properly it is safe and most babies will drink it. What matters most is following the storage times. The CDC says milk that has been refrigerated for 4 days should be used or thrown away, and if anything about a bottle worries you, it’s okay to discard it.

Taking refrigerated milk on the go

The CDC says expressed milk can be stored and transported in an insulated cooler bag with frozen ice packs for up to 24 hours. When you arrive, use the milk right away, refrigerate it, or freeze it, and once the milk is cooled, keep it cool until it is used. The NHS gives the same 24 hours for milk that was already cooled in the fridge. For more, see our breast milk cooler guide.

When to call a doctor or lactation consultant

Call your baby’s doctor if your baby has vomiting, diarrhea, a fever or seems unusually sleepy or unwell after a feed, especially if you think the milk may have been stored too long.

A lactation consultant (IBCLC) can help if you’re struggling to keep up with pumping, have questions about storing milk for a premature baby, or keep running into waste. Our page on breastfeeding support lists where to find help.