Breast Milk Storage Calculator
Enter when you pumped and where you stored it — we'll tell you exactly when it expires.
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GoodBreast Milk Storage Guidelines
Based on CDC guidelines. Always use your judgment — if milk smells off, discard it.
How Long Does Breast Milk Last?
Freshly pumped breast milk can be stored at room temperature for up to 4 hours, in the refrigerator for up to 4 days, and in the freezer for up to 6 months (ideally) or 12 months (acceptable).
The key is to label every bag or bottle with the date and time you pumped, so you always know exactly when it expires. This calculator does that math for you automatically.
If you're building a freezer stash, always use the oldest milk first (FIFO — first in, first out). This ensures nothing goes to waste.
Many moms use this calculator to manage their milk stash and breast milk stash — knowing exactly how many days or weeks of supply they have stored, and which bags to use first. A well-organized breastmilk stash gives you peace of mind, especially when returning to work.
For more pumping tips, read our guide on how to build a breast milk freezer stash or breast milk storage tips for working moms.
Track Your Milk Stash in the App
Our Pumping Tracker app lets you log every session and track your freezer stash — so you always know exactly what you have and when it expires.
About This Breast Milk Storage Calculator
This free breast milk storage calculator tells you exactly when your pumped milk expires based on CDC storage guidelines. Just enter the date and time you pumped and where you stored it — room temperature, fridge, or freezer — and get a clear expiration time.
Fresh breast milk lasts up to 4 hours at room temperature (77°F / 25°C), up to 4 days in the refrigerator (40°F / 4°C), and 6–12 months in a standard freezer (0°F / -18°C). These timeframes are for healthy, full-term babies — if your baby is premature or immunocompromised, your healthcare provider may recommend shorter windows.
Labeling every bag or bottle with the pump date and time is one of the simplest ways to avoid wasting milk. Many moms find that the "first in, first out" system works well — use the oldest milk first to minimize waste. If you're building a freezer stash, our Milk Stash Calculator can help you set a realistic goal.
Remember: these are maximum storage times. Milk quality gradually decreases over time as some nutrients and antibodies break down. Using milk within the first few days of refrigeration or the first 6 months of freezing gives your baby the freshest nutrition.