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BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and all opinions about the products are our own. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.Read more 
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How we decided

We purchase every product we review with our own funds — we never accept anything from product manufacturers.

30 Models Considered
8 Hours Researched
2 Experts Interviewed
210 Consumers Consulted
Zero products received from manufacturers.

We purchase every product we review with our own funds — we never accept anything from product manufacturers.

Buying guide for best breast milk storage bags

There’s a reason many refer to breast milk as “liquid gold” — it’s invaluable for your baby. Breast milk meets your baby’s nutritional needs and contains the antibodies your baby needs to ward off viruses, diseases, bacteria, and more. Plus, it saves you from buying pricey formula.

But pumping breast milk takes time, and time is in short supply for new moms. Because breast milk is so valuable, you don’t want to waste a drop. You need reliable storage bags to keep your liquid gold safe.

Breast milk storage bags are designed to safely hold mother’s pumped milk until it’s time to use it. Many are marked with measured increments, so you know just how much nutrition your baby is getting. Most are freezer-safe, so you can keep milk on hand for when mom’s unavailable or when baby needs a little extra sustenance to keep up with a growth spurt.

Keep reading to learn more about breast milk storage bags. When you’re ready to buy, check our recommendations for the bags that would work best for your situation.

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Always wash your hands with soap and warm water before handling fresh or frozen breast milk.

Key considerations

It’s hard to judge which factor is most important: getting the milk into the bag, storing it handily, or getting it back out without spilling. The best bags do all three with ease.


Breast milk storage bags that attach directly to your breast pump are by far the easiest to fill. If you have a pump you love, look for bags that fit well with your machine. Some pump brands manufacturer bags that work well with their own machines. Other bags are made to fit a wide variety of machines. A number require adapters to fit specific pumps.

If you can’t find bags that work with your pump, you’ll need to fill them from the pump’s bottle. Look for bags with large zipper-lock openings that have plenty of room for the bottle opening. Self-standing bags can be filled more easily than those that need lots of propping. Don’t fill bags completely, since water is a major component of breast milk, and it expands as it freezes.


It’s best to use refrigerated breast milk within three days of pumping. Otherwise, plan on freezing and storing your milk. Bags must be freezer-safe and fold relatively flat so you can stack them in the freezer. Consider placing your stacks in a hard-sided food storage container, as bags left exposed on freezer shelves are prone to damage that could result in leakage.

Bag size

Most breast milk bags hold between 5 and 6 ounces of milk, although a few outliers hold up to 8 ounces. Smaller bags should hold more than enough for babies who are under six months old. Most babies under the half-year mark drink around 25 ounces a day, divided among multiple feedings.

Babies older than six months can eat up to 9 ounces in a single feeding, so moms of big eaters may be good candidates for larger bags. Still, it may make more sense to use multiple small bags, since milk that’s been thawed for 24 hours or more should really be tossed.

When comparing bags, you should also keep the following in mind.

  • All breast milk storage bags should be free of BPA, PVC, and phthalates. 
  • Thicker bags have fewer leaks and protect better against vitamin loss, but they may take longer to thaw and require more room in the freezer.
  • Breast milk storage bags should always come pre-sterilized for your baby’s safety.
  • Some high-quality bags are manufactured with extra seals, top and bottom, for the sake of security and hygiene.
  • If your baby is six months or younger and takes three bottles per day at daycare, you will need at least 60 bags per month. If your baby takes only a handful of bottles a month, you can get by with a smaller package of bags. Breast pump bags may come in packs with as few as 20 or more than 100.
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For your safety
Never add warm breast milk to a bag of frozen breast milk. The warm liquid may thaw the frozen milk, which makes it vulnerable to bacterial contamination. If you must combine, cool the fresh milk first.


Pre-printed measurements

It’s critical to know your baby is getting enough food, especially if she was a preemie or has other health challenges. Look for bags that have incremental markings showing how many ounces or milliliters they hold.


When you’re pumping milk, it’s important to be organized. The best bags should include waterproof labels large enough to write the date you pumped. This will allow you to cycle through your milk by date. Labels must also be large enough to fit your child’s name so childcare workers can make sure the right child gets the right bottle.

Non-toxic pens

When it comes to babies, you can’t take chances. Ink from standard pens or markers may contain questionable substances that you can’t risk leaching through the bag into breast milk. If this concerns you, look for storage bags that come with non-toxic pens or markers that will leave clear, easy-to-read lettering on bag labels.

Doubling up

Even the best-made bag is a bust if the zipper fails. Many quality bags are double-zipped to give you an extra layer of security. That way, you’re less likely to lose your liquid gold if one zipper fails. Look for zippers that open easily; struggling with a stubborn closure makes spills more likely. A number of bags also employ double layers or reinforced seams to keep milk from leaking.

"Do not reuse breast milk storage bags."


Electric breast pump: Medela Pump in Style Double Electric Breast Pump
Pumping has never been easier thanks to this hospital-grade machine from Medela. It’s

scientifically designed to cut pumping time by boosting efficiency and milk flow. Its simplified controls are easy to operate, yet you still have multiple options for speed and vacuum strength. And it’s easy to take along, since it’s built into a backpack that comes complete with an insulated cooler compartment.

Manual breast pump: Philips Avent Manual Comfort Breast Pump
Not all moms need or want a pricey electric pump. This tool is gentle on the hands,

the breast, and the wallet. It’s compact enough to fit in a purse and has only four total pieces to clean.

Breast pump bag: Charlie G. Bags “The New Yorker” Breast Pump Bag
Motherhood isn’t all pastels and ponytails. This elegant tote was created by a working mom, and it shows. Its storage space is unrivaled, and offers thoughtful compartments to keep your pumping supplies, milk, and daily personal items separate. It holds even the largest electric pumps and can be carried tote-style or worn cross-body.

Breast pads: Bamboobies Washable Nursing Pads
Protect against embarrassing leaks and chafing with these super soft, reusable nursing pads. A luxurious cotton/bamboo blend keeps you dry and comfortable from the inside, while a waterproof outer lining keeps your outerwear looking great. What’s more, they’re better for the environment than single-use nursing pads.

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For your safety
It’s safest to toss thawed bags of milk that remain unused after 24 hours.

Breast milk storage bag prices

Inexpensive: The least-expensive economy packs cost around .13 per bag. You can find bags ranging from 5 ounces to 7 ounces at this price. They’ll likely be single-zip and feature graduated measurement markings, although the markings may not be the most accurate. Most will be self-standing for easy filling.

Mid-range: The next tier of breast milk storage bags will cost around .15 per bag. Bags in this price range come in both standard and larger sizes. They should have accurate measurement markings and labels that simplify organization. Construction will be better than less-expensive packs and include reinforced seams, double zippers, and possibly double-layered bags.

Expensive: You’ll pay between .18 and .20 per bag for the highest-quality breast milk storage bags. You’ll find larger bags, as well as smaller bags with a lot of extras, in this top bracket. All should be double-zip bags with reinforcements to make leaks practically impossible. They should have large labels and may come with non-toxic pens for marking. Many will have extra sealing precautions so you can be absolutely sure your bags are safe and sterile.

Buyers should note that the prices above are ballpark figures. The price you pay is also affected by the quantity you buy. For the most part, the more you buy, the more you save. Packs of 20 or fewer may cost up to .40 per bag, while economy-sized boxes whittle the price for most down to less than a quarter per bag.


  • Breast milk can be stored in the back of your refrigerator up to five days, although it’s best to use or freeze it within 36 hours of pumping.
  • Keep a few bags on hand that have only one or two ounces of milk. You can use this milk to boost intake in case of a growth spurt.
  • If you’re pumping at work, it’s safe to store breast milk using ice packs and a cooler.
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While some breast milk storage bags are labeled as microwave safe, most experts do not recommend microwaving breast milk.


Q. How much milk should I store in a bag?
Most bags hold between 5 and 6 ounces of milk, but that doesn’t mean you should fill them to capacity. It’s not unusual for babies to resist the bottle when mom first returns to work, so sending full bags to the sitter may result in many wasted ounces. Start with several bags of 2 to 4 ounces each. If daycare and bottles are old hat to your baby and he’s a good eater, you can fill bags fuller. Still, the higher you fill your bags, the greater the chance of drips, spills, and wasted drops.

Q. What’s the best way to thaw frozen breast milk?
Remove your storage bags from the freezer and place them in the fridge the night before you plan to use them. If you forget, no worries: just put the bag in a bowl of warm water or hold it under the running faucet for a bit. While some bags are advertised as microwave safe, we don’t recommend using this method. Microwaving can thaw milk unevenly and create dangerous hot spots.

Q. How long does frozen breast milk keep?
Frozen breast milk can be stored in the coldest part of your freezer or in a deep freeze for up to a year. However, it’s best to use breast milk within six months of pumping. First, vitamin C content drops the longer the milk is stored. But more importantly, breast milk composition changes over time. The milk your body produces to feed a newborn will not fully meet an older child’s nutritional needs. Be sure to label each bag with the date it was pumped, and use older bags first.

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