Enter when you pumped and where the milk is stored to see exactly when it should be used by, based on CDC breast milk storage guidelines, plus how much time is left and what happens if you move it to the fridge or freezer.
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oz
Enter your values to see the result.
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How to use the Breast Milk Storage Calculator
Enter the date and time you pumped (or when the milk fully thawed, or when the feeding ended).
Choose where the milk is stored: room, cooler, fridge, freezer, thawed or leftover.
Optionally add the amount for the bag label.
Read the use-by time and how much time is left.
Copy the label or print it for your milk bags.
CDC breast milk storage chart
Type of milk
Countertop (77°F / 25°C or colder)
Refrigerator (40°F / 4°C)
Freezer (0°F / −18°C or colder)
Freshly expressed or pumped
Up to 4 hours
Up to 4 days
Within 6 months is best; up to 12 months is acceptable
Thawed, previously frozen
1–2 hours
Up to 1 day (24 hours)
Never refreeze
Left over from a feeding
Use within 2 hours after the baby finished feeding
Source: U.S. Centers for Disease Control and Prevention (CDC) guidance on proper storage and preparation of breast milk, for healthy full-term babies. An insulated cooler bag with frozen ice packs keeps freshly pumped milk for up to 24 hours.
How the use-by time is calculated
The calculator adds the CDC storage limit to the time you enter. Hour limits (4 hours, 24 hours) are added exactly; day and month limits keep the same clock time, so milk pumped at 8:00 AM on the 3rd and kept in the fridge should be used by 8:00 AM on the 7th. For thawed milk the clock starts when the milk is fully thawed, and for leftovers it starts when the feeding ends.
Safe handling tips
Wash your hands and use clean pump parts and containers made for breast milk.
Label every container with the date and time pumped; use the oldest milk first.
Freeze in small portions (2–4 oz) and leave space at the top because milk expands.
Thaw gently in the fridge overnight, under lukewarm running water or in a bowl of warm water. Never microwave breast milk.
Swirl, don’t shake, to mix the fat that separates; separation is normal.
Frequently asked questions
How long can breast milk stay at room temperature?
Freshly pumped breast milk can stay at room temperature (77°F / 25°C or cooler) for up to 4 hours, according to the CDC. Thawed milk at room temperature should be used within 1 to 2 hours.
How long is breast milk good in the fridge?
Freshly pumped breast milk keeps in the refrigerator (40°F / 4°C) for up to 4 days. Store it at the back of the fridge, not in the door, where the temperature is more stable.
How long can breast milk be frozen?
In a freezer at 0°F (−18°C) or colder, breast milk is best used within 6 months, and is acceptable for up to 12 months. Freeze it in small portions of 2 to 4 oz and label each bag with the date.
How long is thawed breast milk good for?
Milk thawed in the refrigerator can be used within 24 hours, counted from when it is fully thawed, not from when you took it out of the freezer. Once brought to room temperature or warmed, use it within 1 to 2 hours. Never refreeze thawed milk.
How long is leftover breast milk good after a feeding?
If your baby did not finish the bottle, use the leftover milk within 2 hours after the feeding ended, then throw it away. Bacteria from the baby’s mouth can grow in the milk.
Can I combine milk from different pumping sessions?
Yes, once both are cooled to the same temperature in the fridge. Label the container with the date of the oldest milk and use that date for the use-by time.
How long can I keep breast milk in a cooler bag?
In an insulated cooler with frozen ice packs, freshly pumped milk can be kept for up to 24 hours, for example while traveling. Then use it, put it in the fridge or freeze it.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.