If you are wondering whether you can reheat prepared formula, you are not alone. This is one of the most common bottle-feeding questions parents ask, especially when trying to avoid waste and make feeding routines easier. The short answer is that untouched prepared formula can be stored safely and warmed later, but a bottle your baby has already started drinking from should not be saved for another feeding.
Below is a simple guide to when reheating formula is okay, when it is not, and how to warm refrigerated formula more safely.
Can You Reheat Prepared Formula?
Yes, but only in certain situations. If you prepared a bottle and your baby has not started drinking from it, that bottle can be refrigerated and used later within the recommended safe storage window. If your baby has already fed from the bottle, the leftover formula should be thrown away rather than saved for another feeding.
That is because saliva mixed into the bottle can increase bacterial growth once the feeding has started.
How Long Can Prepared Formula Sit Out?
If prepared formula is left at room temperature, it should be used within 2 hours of preparation. Once your baby starts feeding, the bottle should be used within 1 hour. After that, any leftover formula should be discarded.
If you do not plan to use the prepared bottle soon, refrigerate it promptly and use it within 24 hours.
How to Reheat Refrigerated Formula
If a prepared bottle has been refrigerated and has not been used yet, you can warm it before feeding if you want to. A bottle warmer is one option, but warming is not strictly necessary. Many babies will take formula at room temperature or cool from the refrigerator.
If you prefer to warm it, place the bottle in warm water for a few minutes and then test a few drops on the inside of your wrist. It should feel lukewarm, not hot.
What You Should Not Do
- Do not save formula from a bottle your baby already drank from.
- Do not leave prepared formula sitting out too long.
- Do not microwave formula, because it can heat unevenly and create hot spots.
- Do not reheat the same bottle over and over again.
Helpful Formula Storage and Prep Resources
- Can You Refrigerate or Freeze Formula?
- All Things Formula: Preparation, Storage Life & Quick Tips
- Baby Formula Preparation Guides
- How to Measure Baby Formula Without Scoop
Formula Collections
If you are comparing formula options, you can also browse our European Organic Baby Formula collection and our Stage 1 Formula collection.
When in doubt, the safest approach is to prepare bottles carefully, refrigerate unused bottles promptly, and discard anything that may no longer be safe. If you have concerns about formula handling for your baby, check with your pediatric professional.