How long is breast milk good for?

For healthy, full-term babies: up to 4 hours at room temperature, up to 4 days in the refrigerator, and best used within 6 months in the freezer (acceptable up to 12). Thawed milk keeps 24 hours in the fridge, and once your baby starts a bottle, use it within 2 hours.

Storage times at a glance

Store milk in the back of the freezer, the coldest area, rather than in the door.

Handling and storage tips

• Wash your hands and use clean, food-grade containers (hard plastic or glass with tight lids) or breast milk storage bags. Avoid ordinary disposable bottle liners or thin zip bags.
• Label with date and time, plus your baby's name if the milk is going to childcare. Store in small portions of 2 to 4 oz (60 to 120 mL), plus a few 1 oz top-off bags to reduce waste.
• Leave a little headspace when freezing, because milk expands.
• To combine milk from different sessions, chill fresh milk in the refrigerator first before adding it to already-cold milk. Label with the date of the oldest milk.
• Thaw safely: overnight in the fridge, or under cool running water moving to warm. Never microwave. Swirl gently to mix the fat rather than shaking hard.
• If milk smells soapy, usually from higher lipase, it's typically still safe if stored within these times. Trust your senses and discard milk that smells truly rancid.
• Once your baby starts a bottle, use it within 2 hours, then discard any leftover.
• Never refreeze thawed milk.

Special situations

Hot environments (above 77F / 25C)

This covers a hot day with no air conditioning, a car, or being outdoors.

• Room temperature: aim for 1 to 2 hours maximum
• Use an insulated cooler with fully frozen ice packs if milk will be out longer
• Never leave milk in a parked car

Traveling, or no refrigerator available

• Pack milk next to fully frozen ice packs in a high-quality cooler, and pre-chill the cooler if you can
• Freshly pumped milk kept cold in a cooler with ice packs is generally safe for up to 24 hours
• Then move it to a refrigerator (use within 4 days) or freeze it
• For flights, plan extra ice packs and leak-proof bags, and carry milk with you rather than checking it

Preterm, hospitalized, or immunocompromised babies

Follow your NICU's policies, which are stricter than general guidance.

• Room temperature: limit to 1 hour
• Refrigerator: up to 24 hours. Some units allow 48, so follow your care team's rule.
• Warming or a started bottle: use within 1 hour, then discard