Published November 29, 2023

How Long Is Formula Good For (And Other Formula Preparation Questions)

Let’s face it, baby formula can be expensive and the last thing parents want is to waste it– that feels like money down the drain! In order to keep your baby safe and minimize waste, parents should be aware of food safety rules that apply to formula preparation and storage. 

Read on for a full explanation of the time frames and considerations to follow as you feed your baby formula.

How Long is a Bottle of Formula Good For?

First things first! Food safety rules for baby formula are different from those you may be familiar with for breast milk. Generally speaking, a formula bottle is good for a significantly shorter period of time at room temperature and in the fridge, and formula cannot be frozen for later use like breast milk can. Why is this? Breast milk contains bioactive components, including immune factors and antimicrobial properties, that formula does not. These bioactive components help preserve breast milk and prevent bacterial contamination over longer periods. 

This does not mean that formula is unsafe! Only that parents must be aware that the guidelines differ. If you’re formula feeding, the guidelines that you must follow depend on the formula type you’re using and at what temperature the formula is being stored.


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On the Counter

Formula that has been prepared but has not yet been served to your baby is good at room temperature for up to 2 hours. This is true for powdered formula, liquid ready-to-feed formula (that has been opened), and concentrated formula that has been opened and prepared.

Be aware that once your baby’s bottle has touched their lips, however, the bottle must be used or tossed within 1 hour! This is because bacteria can be introduced from your baby’s mouth, and the longer the formula sits out, the higher the likelihood that bacteria will multiply to an unsafe level. After baby drinks some, you have 60 minutes to use that bottle of formula before it expires.

In the Fridge

According to the American Academy of Pediatrics, powdered baby formula that has been prepared but not yet offered to baby will last in the fridge for up to 24 hours. That’s right– you can prepare a batch of formula in bulk, up to a day’s worth, and keep it in the fridge until you need it! Liquid ready-to-feed formulas and concentrated formulas are good for even longer; these can be refrigerated for up to 48 hours. 

Any powder formula that you have prepared with water should be kept in a sealed container, such as a formula mixing pitcher or in individual bottles, while unused ready-to-feed or concentrated formulas should remain in their original container with the provided lid or in individual, capped bottles. 

Can You Reheat Baby Formula?

Unfortunately no, once a bottle of formula has been heated it must be used within 1 hour. If parents prefer to offer warm bottles, they should be heated immediately before each feeding using a bottle warmer or a mug of hot water– never the microwave! Given the shorter window for how long formula stays good after heating, many parents choose to offer their baby room temperature formula or even chilled formula straight from the fridge. That’s right! You do not need to heat your baby’s formula bottle before serving!

How Long Does a Can of Formula Last?

Formula manufacturers take a variety of steps to ensure that their products have a long shelf-life, and this is good news! If you follow safe storage guidelines, the formula in your cabinets or pantry can last a long time, even years, before it starts to lose nutritional value or go rancid. As with bottles of prepared formula, how long your container of formula will stay good depends on whether it’s been opened and the temperature where it is stored.

Opened, Unmixed Formula

Many parents don’t realize that they only have 30 days to use a container of formula once it has been opened. All powdered formulas, regardless of brand or individual expiration dates, must be used within a month of opening! For this reason, parents who are combination feeding or supplementing breast milk with a small amount of formula may want to buy formula in smaller containers, as this reduces the risk of having leftover formula that must be tossed at the end of the 30-day window. 

It is ideal to keep any opened powder in the original container and to store your formula in a cool, dry place. If you need to transfer your opened powder formula from the original tub or can, you must use a sterilized container that seals and is water-resistant.

Unopened, Unmixed Formula

How long does baby formula last in the pantry? Formula that is still sealed is good until it reaches the expiration date on the bottom of the container. These expiration dates are typically 18 months to 2 years from the date of manufacture! This long shelf-life makes baby formula a good option to have on hand in case of emergency, even if you’re not sure whether you will need it or use it.

In order to maximize a formula’s shelf-life, sealed formula containers should be stored in a cool, dry place, away from direct sunlight and extreme temperatures. Unopened formula should never be stored in a parent’s car, in a humid cellar or basement, or in a refrigerator or freezer. A cabinet or pantry (away from little hands!) is typically a great option for your formula stash.

Does Baby Formula Expire?

Yes, formula can expire before the expiration date (or before the 30-day open formula use-by window) if food safety guidelines discussed above are not followed. If formula is exposed to excess heat or moisture, or if bacteria is introduced to the formula, your baby’s formula may go bad. Signs that your baby’s formula is no longer good can include changes in:

  • Color, as the formula may become darker or more yellow than is typical
  • Texture, as the formula may be clumpier or harder to scoop
  • Smell, as the formula may have a stronger smell, or smell rancid
  • Taste, as the formula may have a rancid taste 
  • Solubility, as the formula may no longer dissolve as easily and/or contain clumps that are hard to dissolve

In general, if your formula does not have the characteristics that you are familiar with this is cause for concern. If you have questions about something strange or amiss with your child’s formula, please contact the manufacturer and your child’s pediatrician before using. If something seems “off” about your formula, even if it’s within the use-by window, it’s often best to toss it.

Is My Baby Formula Safe?

All infant formula goes through a variety of safety checks to ensure that it is safe to use. Formula is one of the most regulated food products that exists! As important as manufacturers’ safety and quality checks are, it is equally important that parents follow food safety guidelines when preparing and storing formula once it enters their home. By following the storage rules outlined above and using appropriate food hygiene practices (wash your hands and ensure your workspace is clean!), you can mitigate the risk of illness and promote healthy feeding for your baby.

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The content on this site is for informational purposes only and not intended to be a substitute for professional medical advice, diagnosis or treatment. Discuss any health or feeding concerns with your infant’s pediatrician. Never disregard professional medical advice or delay it based on the content on this page.

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