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How Long Is Formula Good For? Everything You Need to Know

How Long Is Formula Good For? Everything You Need to Know

I’m sure you’ve heard of all the benefits of breastfeeding, but don’t let that stop you from trying out the formula, mommies!

If you’re expecting or have a newborn, prepare to enter a complex world of new questions, like “Do I need to boil distilled water for formula?” and “Are there any baby formula alternatives?

After finding a formula, sterilizing your baby’s bottle and nipple, and mixing, it’s time to feed your little one. But what if they get full and don’t finish the whole bottle?

I’ll share my advice on how long baby formula lasts after mixing and when to throw it out. Keep reading, Nanay!

How Long Can a Baby Formula Bottle Sit Out?

After learning how to make baby formula and mix up a bottle, set a timer and get your hungry baby because it doesn’t last very long.

If you’ve mixed the formula ahead of time, it will keep for 2 hours at room temperature before you need to throw it out. It can spoil if you leave it out for too long.

Remember to ensure everything you use to prepare your baby’s formula is clean before you mix anything. Kahit mahal siya, I recommend bottled water as the best water for baby formula.

This ensures the formula isn’t contaminated by the water you use. I’ve also used distilled water without any problems.

How Many Hours Does Mixed Baby Formula Last?

How Many Hours Does Mixed Baby Formula Last?

After mixing your formula, don’t leave it out for too long! I wholeheartedly recommend ensuring your baby finishes their bottle when it is ready.

The mixed formula lasts 2 hours at room temperature before it becomes risky. This applies to all formulas, whether concentrate, powdered, or ready-to-feed.

So if you’re having trouble choosing between Similac or Enfamil, you can cross off “shelf life after mixed” as a consideration. Choose based on nutrients and price instead!

When Refrigerated

Fortunately, you can extend the shelf life of mixed formula by putting it in the fridge. A bottle of formula will be fine for 24 hours if you refrigerate it immediately.

I suggest labeling your baby’s formula bottles with the date and time you mixed them to be safe. This way, you can prepare in the morning and keep your baby fed until the next day!

If you have a clean and open bottle of ready-to-feed formula, it can be kept safely in the fridge for 48 hours.

After Baby Drinks From It

Your mixed formula has a much shorter shelf life once the baby takes a few gulps. If your baby doesn’t finish formula milk, it’ll only be good for 1 hour before going bad.

It won’t spoil immediately, but your baby’s saliva creates a prime environment for bacteria to flourish. Giving your baby old mixed formula might make them sick, so don’t risk it!

Once your little one is old enough, they should be used to eating and drinking other foods. But before they get there, you can prepare them with the best milk for 1-year-olds for more nutrition.

How to Store Opened Baby Formula

How to Store Opened Baby Formula

After you’ve bought the best baby formula for your little one, you’ll have to store it properly to extend its shelf life. You’ll need to know how to store the opened formula and when it’s time to throw it out.

After opening a can of powdered formula, I strongly suggest finishing it a month after opening. 

You can also go by the expiration date, but keeping it for too long might cause bacteria to grow inside the container.

For liquid and ready-to-feed formula, you can store it for up to 24 hours if your baby hasn’t drank from it yet. Otherwise, throw it out after 2 hours.

How to Store Unopened Baby Formula

I understand, nanay. Sometimes your baby suddenly loves their new formula so you buy a big stockpile for him. 

If or when this happens to you, keep your cans or jars of unopened formula inside a cool, dry spot like your pantry or cupboard.

Follow the expiration date and never feed your little one expired formula because they might get sick.

NOTE: If you have no breast milk or formula, your baby can eat purée in a pinch. Kids who are old enough can also stop drinking formula and be weaned off it, especially as they move to more solid foods.

Frequently Asked Questions (FAQs)

Learn more about using baby formula and when you should discard it here.

What Happens if You Use Expired Baby Formula?

Whatever you do, mommies, please don’t use expired baby formula! Expired formula won’t agree with your baby and it’s a big, unnecessary risk.

I understand you can lose track of time when juggling everything your baby needs; maybe you’ve started to transition from breast milk to formula or your little one is sick.

However, ignore that temptation to use expired formulas. Avoid making your baby sick!

Can I Reuse the Unfinished Baby Formula?

Sometimes you make more than your baby can finish, and they leave a few unfinished ounces in the bottle. Don’t be tempted to save money, and throw it out if your baby doesn’t feed again within 1 hour.

Once your baby has started a bottle of formula, they need to finish it and you can’t store it anymore. This might be a problem for some mommies, especially if your baby’s a fussy eater!

No matter how much formula is left in the bottle, if your baby doesn’t finish it, throw it out. Your baby’s saliva has bacteria that can mix with the unfinished formula and make them sick.

If you notice that your baby isn’t finishing their formula anymore, it might be time to learn how to switch baby formulas to ensure bunso gets their nutrition!

What if You Freeze Baby Formula?

Let’s assume you have lots of soy formula and are preparing to leave for work, so you mix multiple bottles and turn to the freezer. But will that work for storage?

Unfortunately, that’s a bad idea. You should not freeze baby formula because it can separate the fat from other ingredients.

It is especially bad for powdered formula since the moisture may cause it to clump up after it’s removed from the fridge. Liquid formula is also prone to separating after it thaws.


Whether you’re using the best baby bottles or not, knowing how long the formula stays good for is important. This is to ensure your baby is getting their nourishment safely.

Always pay attention to the expiration date on your baby’s formula and throw it out immediately once it’s past the expiration date. 

Follow the same advice if your partner or baby’s caregiver has left a bottle of unfinished formula on the counter. Sterilize another bottle and mix some more formula, mama!

Nayna Llenos
Nayna Llenos

Hi, I’m Nayna!
I’ve always wanted to be a mother, and I’m lucky and blessed to have two wonderful children to care for and love.
Despite this blessing, there are times wherein I do wonder if I truly am the mother my children need. Am I giving them the right food, care, and discipline to them?
But that is the beauty of parenting — you grow along with your children as they flourish to be their wonderful selves!
I wish to share my experiences with motherhood and how these tips can help you in your parenting journey.
I hope my advices and experiences will prove useful to you and that you have a smooth and wonderful journey as a mother!