Breast Milk Storage Guidelines: CDC, AAP and NHS Compared
The short answer
The CDC page (updated 2026-08-14) says freshly expressed breast milk keeps up to 4 hours at 77°F (25°C) or colder, up to 4 days in the refrigerator, and about 6 months in the freezer, up to 12 months acceptable. The fridge cell ranges from 72 hours (Healthdirect Australia) to 8 days (NHS). Table 1 shows each wording.
Key takeaways
- Fridge: the CDC and AAP say 4 days, the NHS says up to 8 days at the back of the fridge at 4°C (about 39°F) or colder, and Healthdirect Australia says no more than 72 hours.
- Freezer: the AAP says up to 9 months at 0°F (-18°C) and up to 12 months in a deep freezer at -4°F (-20°C). The NHS says up to 6 months at -18°C. Healthdirect Australia says 3 months with a separate door.
- Room temperature: the CDC says 4 hours. The AAP, Eastern Ontario and Healthdirect Australia name 6 to 8 hours under stated conditions. The NHS page has no room temperature figure.
- Thawed milk in the fridge: the CDC says within 24 hours counted from completely thawed. The AAP says best within 24 hours but may be used within 48-72 hours. The CDC says never refreeze; the AAP page does not address it.
- Table 3 is our arithmetic on the quoted cells. It is not a ranking, and this page does not pick a source.
This page puts the breast milk storage guidelines of named sources side by side for milk that has not been fed yet. For milk left in a bottle after a feed, read about leftover breast milk after a feed.
What do the main sources say about storing freshly expressed breast milk?
Seven pages are in table 1, each opened on 2026-11-01 (dates in the Sources list below). Quotes are the page’s words; “Not stated” means the page, as we read it, has no sentence on the point.
Table 1. What named sources say about freshly expressed breast milk
| Source | Country/year | Room temperature (77°F, 25°C or colder) | Refrigerator | Freezer |
|---|---|---|---|---|
| CDC, Breast milk storage and preparation | US, updated 2026-08-14 | “At room temperature (77°F or colder) for up to 4 hours.” | “In the refrigerator for up to 4 days.” | “In the freezer for about 6 months is best; up to 12 months is acceptable.” No freezer type or temperature named. |
| AAP HealthyChildren.org, Tips for Freezing & Refrigerating Breast Milk | US, last updated 2025-07-07 | Up to 77°F (25°C) for “up to 4 hours”, “or up 6 to 8 hours if very cleanly expressed”. | 39°F (4°C): “It is best to use refrigerated breast milk within 4 days.” Also: “Freeze breast milk if you will not be using it within 48-72 hours.” | Separate-door freezer 0°F (-18°C): “up to 9 months”. Chest or deep freezer -4°F (-20°C): “up to 12 months”. |
| NHS, Storing breast milk | UK, no date shown | Not stated | “at the back of the fridge” “for up to 8 days (at 4C or colder)”, about 39°F. “in the ice compartment of the fridge for up to 2 weeks”. | “in the freezer for up to 6 months (at -18C or colder)”, about 0°F. |
| Arizona Department of Health Services, Breastmilk Storage Guidelines | US, 2020 | “Up to 4 hours”. The column header prints “Up to 85°F/25°C”. | “Up to 4 days” | Separate-door freezer (0°F, -18°C or colder): “Up to 6 months”. Deep freezer (-4°F, -20°C): “Up to 12 months”. |
| Oregon Health Authority WIC, Storing breast milk safely | US, 03/2026 | “Breast milk may be stored at room temperature (up to 77°F) up to 4 hours.” | “Refrigerator should be at 40°F or below.” “Up to 4 days.” | “Freezer 0°F or colder. Use within 6 months is best. Up to 12 months is acceptable.” |
| Healthdirect Australia, Expressing and storing breast milk | Australia, reviewed August 2023 | Up to 26°C (about 79°F): “No more than 6-8 hours.” | Up to 5°C (41°F): “No more than 72 hours.” | “2 weeks in the freezer section of a fridge (-15°C).” “3 months in a freezer with a separate door (-18°C).” “6-12 months in a deep freeze (-20°C).” |
| Eastern Ontario Health Unit, Safe storage and handling of breast milk | Canada (Ontario), no review date | “6 to 8 hours at room temperature (less than 25°C)” | “5 days at the back of the refrigerator” | “3 to 6 months when at the back of the freezer of a refrigerator (-18°C or 0°F)”. “6 to 12 months in chest or upright freezer (-20°C or -4°F)”. |
Table 1 holds one “Not stated” cell: the NHS room temperature cell. The Arizona sheet was adapted, it says, from AAP books and the Academy of Breastfeeding Medicine (ABM) Clinical Protocol #8 (2017). We opened the protocol’s PubMed page, which shows no abstract, so it has no row. How we source explains how a source gets in.
How long can breast milk sit out?
Sources give 4 hours or 6 to 8 hours. Four pages give 4 hours: the CDC and Oregon at 77°F or colder, the AAP at up to 77°F (25°C) as its first figure, and Arizona, whose column header prints “Up to 85°F/25°C”. On the Arizona sheet 85°F is not 25°C, so this page uses only its hours and days. The CDC page gives one figure, 4 hours.
The AAP sentence goes on: “or up 6 to 8 hours if very cleanly expressed; however, it is best to chill as soon as possible.” The AAP page also gives “4 hours at room temperature and 4 days in the refrigerator” as “a more conservative approach”. Healthdirect Australia and Eastern Ontario give 6 to 8 hours, at up to 26°C (about 79°F) and less than 25°C. The NHS page has no room temperature figure.
How long does breast milk last in the fridge?
The CDC, AAP, Arizona and Oregon pages say 4 days. The NHS says up to 8 days at the back of the fridge at 4°C or colder (about 39°F), and up to 2 weeks in the ice compartment. Eastern Ontario says 5 days. Healthdirect Australia says “No more than 72 hours”, which is 3 days. The gap is arithmetic: 8 days minus 4 days is 4 days, and 8 days minus 3 days is 5 days (table 3).
How long does breast milk last in the freezer?
The CDC says “about 6 months is best; up to 12 months is acceptable” and names no freezer type or temperature. Oregon words it the same way, for a freezer at 0°F (-18°C) or colder. Arizona and the NHS say up to 6 months (the NHS at -18°C or colder, about 0°F).
The AAP separates freezer types: up to 9 months with a separate door at 0°F (-18°C), up to 12 months in a chest or deep freezer at -4°F (-20°C). Healthdirect Australia and Eastern Ontario also separate them (table 1). For a deep freezer, the AAP, Arizona, Eastern Ontario and Healthdirect Australia all give 12 months as the upper figure.
What do sources say about thawed breast milk?
The sources count the clock from different points, and some give no time. Quotes are exact.
Table 2. What named sources say about thawed breast milk
| Source | Thawed in the fridge | Brought to room temperature or warmed | Refreezing |
|---|---|---|---|
| CDC | “If you thaw breast milk in the refrigerator, use it within 24 hours.” “Start counting the 24 hours when the breast milk is completely thawed, not from the time when you took it out of the freezer.” | “Once breast milk is brought to room temperature or warmed, use it within 2 hours.” | “Never refreeze breast milk after it has thawed.” |
| AAP | “Once breast milk is thawed, it can be stored in a refrigerator; it is best used within 24 hours, but may be used within 48-72 hours.” | Not stated | Not stated |
| NHS | No number of hours. “The best way to defrost frozen breast milk is by leaving it in the fridge to thaw out completely before use.” Then: “Whichever way you defrost the milk, it must be used immediately and you should throw away any leftover milk after feeding.” | Same sentence as in the previous column; no separate time. | “Never re-freeze defrosted milk.” |
| Arizona DHS | Row “Thawed Breastmilk Previously Frozen”: “Up to 1 day (24 hours)” | “Up to 2 hours” | “Avoid re-freezing thawed breastmilk” |
| Oregon WIC | “Use breastmilk within 24 hours of thawing it in the refrigerator. This means 24 hours from when the breastmilk is no longer frozen, not from when you take it out of the freezer.” | “Once breast milk is thawed to room temperature or warmed after being in the refrigerator or freezer, use it within 2 hours.” | “Do not re-freeze breast milk.” |
| Healthdirect Australia | Up to 5°C (41°F): “No more than 24 hours.” | Thawed, not warmed, up to 26°C (about 79°F): “No more than 4 hours once thawed.” Thawed and warmed: “If the baby has not begun feeding store for up to 4 hours in fridge.” | “Don’t refreeze milk that has been thawed.” |
| Eastern Ontario Health Unit | “Use the milk within 24 hours of taking it out of the freezer.” | “Warm the thawed breast milk by placing it in a bowl of warm water. Milk is to NEVER be warmed up in a microwave and must be used within one hour of being heated.” | “NEVER refreeze previously thawed breast milk.” |
The 24 hours start at different points. The CDC and Oregon count from when the milk is completely thawed. Eastern Ontario counts from “taking it out of the freezer”. The NHS gives no number. The clock for milk left after a feed is on the leftover page; this table quotes only the thawed and warmed rows.
Where do the sources differ?
Table 3 is our arithmetic on the cells of tables 1 and 2. It subtracts one quoted figure from another and picks no winner.
Table 3. Gaps between named sources (our arithmetic)
| Question | Lowest figure and source | Highest figure and source | Gap |
|---|---|---|---|
| Room temperature, hours | 4 hours (CDC, AAP first figure, Arizona, Oregon) | 8 hours (“6 to 8 hours”: AAP if very cleanly expressed, Eastern Ontario, Healthdirect Australia) | 8 - 4 = 4 hours |
| Fridge, days | 3 days (Healthdirect Australia, “72 hours”) | 8 days (NHS, back of the fridge, 4°C or colder) | 8 - 3 = 5 days |
| Freezer, first figure each page gives (type and temperature as each page states; the CDC states none) | 3 months (Healthdirect Australia, separate door; Eastern Ontario starts its range at 3) | 9 months (AAP, separate door, 0°F, -18°C) | 9 - 3 = 6 months |
| Freezer, counting “acceptable” | 3 months (Healthdirect Australia) | 12 months (“up to 12 months is acceptable”: CDC, Oregon) | 12 - 3 = 9 months |
| Thawed milk in the fridge, hours | 24 hours (CDC, Arizona, Oregon, Healthdirect Australia, Eastern Ontario) | 72 hours (AAP, “may be used within 48-72 hours”) | 72 - 24 = 48 hours |
Table 3 does not count “freeze if” sentences as fridge limits. The AAP says to freeze “if you will not be using it within 48-72 hours”, and Healthdirect Australia says “Freeze milk that will not be used with 2 days” (the page’s spelling). Both sit on the pages with their fridge figures, and the AAP “may be used within 48-72 hours” in the last row is a separate sentence about thawed milk.
The pages differ in date, country and assumptions: freezer type, fridge temperature, and whether the milk is “best” within a time or limited to it. This page says nothing about which figure is right.
Example, hypothetical. A batch expressed on Monday 2026-11-02 at 08:00, counted from 08:00 with each source’s numbers. Each window is counted on its own, as if the milk went straight to that place at 08:00.
Table 4. Example, hypothetical: end of each window for one batch
| Window | CDC | AAP | NHS | Healthdirect Australia |
|---|---|---|---|---|
| Room temperature | 2026-11-02 12:00 | 12:00; or 14:00 to 16:00 if very cleanly expressed | Not stated | 14:00 to 16:00 |
| Refrigerator | Fri 2026-11-06 08:00 | Fri 2026-11-06 08:00 | Tue 2026-11-10 08:00 | Thu 2026-11-05 08:00 |
| Freezer, as each page words it | 2027-05-02 (6 months, “best”); 2027-11-02 (12 months, “acceptable”) | 2027-08-02 (9 months, separate door) | 2027-05-02 (6 months) | 2027-02-02 (3 months, separate door) |
Arithmetic:
- Hours: 08:00 + 4 hours = 12:00. 08:00 + 6 to 8 hours = 14:00 to 16:00.
- Days: Monday 2026-11-02 + 3 days = Thursday 2026-11-05. + 4 days = Friday 2026-11-06. + 8 days = Tuesday 2026-11-10.
- Months: 2026-11-02 + 3 months = 2027-02-02. + 6 months = 2027-05-02. + 9 months = 2027-08-02. + 12 months = 2027-11-02.
The month rows count calendar months. We found no definition of a month in the pages we read.
What about milk left in the bottle after a feed?
That is a different clock from the one in these tables. Our leftover milk table puts the sources side by side, including the CDC sentence for a bottle the baby did not finish.
What do you write on a bag or in a log?
Sources that mention labeling ask for a date. The CDC says “Clearly label breast milk with the date it was expressed.” The NHS says “remember to label and date it.” Healthdirect Australia says “Write the date and time you expressed on the container.” The CDC also says “Store in 2 to 4 ounces or the amount offered at one feeding,” which is about 60 to 120 ml (2 fl oz is 59 ml, 4 fl oz is 118 ml).
Example: you express 150 ml (about 5 fl oz) on Monday 2026-11-02 at 08:00 and split it into two bags of 75 ml (about 2.5 fl oz) each. Each label reads: “Mon 2026-11-02 08:00, 75 ml (2.5 fl oz), bag 1 of 2”. Arithmetic: 150 / 2 = 75 ml. 75 / 29.5735 = 2.54 fl oz, shown as 2.5. Each bag is inside the CDC’s 2 to 4 ounce size.
Get the free printable bottle feeding log, with columns for offered, left and drank and a box for the time. Rememilk, the bottle log we are building, is in development. The printable works without it.
What this page is, and what it is not
This page quotes named sources and gives no medical advice. We are parents, not medical professionals, and the sentences in the tables belong to the sources. Arizona gives its times for healthy full-term babies, and Eastern Ontario gives its fridge figure "for healthy full-term babies". If your baby was born early or is unwell, ask your care team or hospital, which may have its own rules.
Sources change and some are older than others. Each entry in the Sources list has a "Last checked" date, and two pages carry old dates (Arizona 2020, Healthdirect Australia 2023). The source method page lists how often we re-open each page. Read who writes here for the author's role.
Frequently asked questions
How long can breast milk sit out?
The CDC page says freshly expressed milk keeps up to 4 hours at 77°F (25°C) or colder. The AAP also says 4 hours and adds 6 to 8 hours if very cleanly expressed, and Healthdirect Australia says no more than 6-8 hours up to 26°C. The NHS page has no room temperature figure.
How long does breast milk last in the fridge?
The CDC and AAP pages say up to 4 days. The NHS says up to 8 days at the back of the fridge at 4°C or colder, Eastern Ontario says 5 days, and Healthdirect Australia says no more than 72 hours.
How long does breast milk last in the freezer?
The CDC says about 6 months is best and up to 12 months is acceptable. The AAP says up to 9 months at 0°F (-18°C) and up to 12 months in a deep freezer at -4°F (-20°C). The NHS says up to 6 months at -18°C or colder.
Can you refreeze thawed breast milk?
The CDC says "Never refreeze breast milk after it has thawed." The NHS says "Never re-freeze defrosted milk." The AAP page does not address refreezing in the passages we read.
Do storage times change for premature or sick babies?
The Arizona sheet says "Storage times and temperatures may vary for premature or sick babies" and to check with a health care provider, and Eastern Ontario says early premature babies "require special precautions". The AAP editor's note says its guidelines are "appropriate for babies born premature and those who are hospitalized", and that "hospitals may have their own rules". The CDC page text we read has no premature baby sentence.
Sources
- CDC, Breast milk storage and preparation
- AAP HealthyChildren.org, Tips for Freezing & Refrigerating Breast Milk
- NHS, Storing breast milk
- Arizona Department of Health Services, Breastmilk Storage Guidelines
- Oregon Health Authority WIC, Storing breast milk safely
- Healthdirect Australia, Expressing and storing breast milk
- Eastern Ontario Health Unit, Safe storage and handling of breast milk
Rememilk is a bottle milk log in development
It keeps offered, left and drank for every bottle, and nursing you cannot measure.