How long is formula good after mixing?
Two clocks start the moment you mix a bottle: one for the bottle sitting out, and a shorter one once your baby starts drinking. Here is what the CDC and the American Academy of Pediatrics say.
The short version, from the CDC:
Use prepared formula within 2 hours of preparation.
Once feeding begins, use it within 1 hour.
Not using it within 2 hours? Put it in the fridge right away and use it within 24 hours.
Prepared formula chart
| Situation | How long it is good |
|---|---|
| Mixed, at room temperature, baby has not started | Within 2 hours of preparation |
| Baby has started drinking from the bottle | Within 1 hour from when feeding begins |
| Mixed and put straight in the fridge | Within 24 hours |
| Left in the bottle after the feed | Throw it out |
Mixing a whole day of formula at once? The same 24 hour fridge limit applies to the batch: see the formula pitcher method, step by step.
Why the clock is shorter once baby starts drinking
When your baby drinks, saliva gets into the bottle. The CDC explains that the combination of formula and your baby's saliva can cause bacteria to grow. That is why it says to throw out any formula left in the bottle after a feed, even if it looks fine, instead of saving it for the next one.
Can you put a half finished bottle back in the fridge?
No. Once your baby has fed from it, the leftover formula should be thrown out, not refrigerated for later. The American Academy of Pediatrics suggests making smaller batches, 2 to 4 ounces at a time, so you pour less down the drain.
What about an opened container of powder?
Check the label on your formula. The CDC notes that most infant formulas need to be used within 1 month of opening the container. Keep it in a cool, dry place with the lid tightly closed.
Common questions
How long is formula good at room temperature?
Up to 2 hours from when you prepared it, as long as your baby has not started drinking from it.
How long is formula good in the fridge?
Up to 24 hours, if it went into the fridge right after mixing.
How long is formula good after baby drinks from it?
Up to 1 hour from when feeding began. Throw out whatever is left after that.
Sources
- CDC, Infant Formula Preparation and Storage: cdc.gov
- American Academy of Pediatrics, How Long Can Baby Bottles Sit at Room Temperature?: healthychildren.org
Written by the FeedEase team. Every number on this page is checked against the sources above. This is general information, not medical advice: every baby is different, so check with your pediatrician.
