Baby and Parenting Calculators
Breast milk use-by.
Pick how the milk is stored, enter when it was pumped (or when it finished thawing) and see the use-by time and how long is left. Runs in your browser; nothing is sent or stored.
Your numbers
Result
Fill the form and press Calculate.
Not medical advice. These are general guidelines for healthy full-term babies. Babies who are premature, ill or in hospital may have stricter rules, so follow your care team’s advice. When in doubt, throw it out.
Worked example
Milk pumped at 8:00 am on Monday and kept in the fridge is good until 8:00 am Friday (4 days). The same milk frozen at 8:00 am on 31 August is best used by 28 February (6 months) and acceptable until 31 August the next year (12 months).
How it works
The CDC gives these limits for freshly expressed milk: up to 4 hours at room temperature (77 F / 25 C or colder), up to 4 days in the refrigerator, and in the freezer about 6 months is best and up to 12 months is acceptable. For thawed milk: use within 24 hours if thawed in the refrigerator, counting from when it is completely thawed, and within 2 hours at room temperature or once warmed. Do not refreeze.
The calculator adds those periods to the time you enter. Months are calendar months, so 31 August plus 6 months is 28 February.
Sources and basis: U.S. Centers for Disease Control and Prevention, Breast Milk Storage and Preparation (cdc.gov, page last reviewed 2026-03-25; checked 2026-10-05). Canadian guidance from the Canadian Paediatric Society and your public health unit is similar; follow your local advice if it differs.
FAQ
How long can pumped breast milk sit out?
Up to 4 hours at room temperature of 77 F (25 C) or colder, according to the CDC.
How long is breast milk good in the fridge?
Up to 4 days for freshly expressed milk.
How long does frozen breast milk last?
About 6 months is best and up to 12 months is acceptable in a freezer.
How long is thawed breast milk good for?
Within 24 hours if thawed in the refrigerator, counted from when it is fully thawed. Within 2 hours at room temperature or once warmed. Never refreeze it.
Can I use the date I pumped for frozen milk?
Yes. Start the freezer clock on the day the milk went into the freezer. The calculator uses the date and time you enter.