To warm formula from the fridge, place the sealed bottle in a bowl or container of warm water, or hold it under warm running water for a few minutes. Swirl the bottle, then test a few drops before feeding. The formula should feel lukewarm—not hot. Never microwave infant formula because microwaves can create hot spots that burn a baby's mouth.
Warming is optional. According to the FDA, infant formula does not need to be warmed, so you can offer a properly refrigerated bottle cold if your baby accepts it.
This guide applies to prepared formula that was refrigerated before your baby drank from it. Never save or reheat formula left over from a feeding.
How to Warm Formula From the Fridge: Step by Step
- Check the time. Use refrigerated prepared formula within 24 hours of preparation and follow any stricter instructions on the product label.
- Keep the bottle sealed. This helps prevent water from entering the bottle or touching the nipple.
- Use warm water. Place the bottle in a bowl of warm water or hold it under warm running water for a few minutes. Do not use boiling water.
- Swirl the bottle. Gently mix the formula so the temperature is even.
- Test the temperature. Put a few drops on your wrist or hand. It should feel lukewarm, not hot.
- Feed promptly. Once your baby starts drinking, use or discard the bottle within 1 hour.
Quick Safety Guide
| Question | Answer |
|---|---|
| Does refrigerated formula need to be warmed? | No. It can be served cold if your baby accepts it. |
| Can you warm formula in a bowl of water? | Yes. Keep the bottle sealed and use warm, not boiling, water. |
| Can you use a bottle warmer? | Yes, if you follow the device and formula manufacturer's instructions and check the temperature before feeding. |
| Can you microwave formula? | No. Microwaves can create dangerous hot spots. |
| Can you reheat formula twice? | Do not repeatedly warm and cool the same bottle. Warm only what you plan to feed. |
| Can you warm a bottle the baby already drank from? | No. Discard leftovers within 1 hour from the start of feeding. |
Can You Reheat Prepared Formula?
The clearer term is warm rather than reheat. You may warm a refrigerated bottle that was stored safely and has not been offered to your baby. Do not take a partially used bottle from an earlier feeding and heat it again.
The safe storage window still applies. Prepared formula should be used within 2 hours of preparation or refrigerated promptly and used within 24 hours. Warming does not restart that clock. See our separate guide, Can You Refrigerate or Freeze Baby Formula?, for the complete storage rules.
How Warm Should Baby Formula Be?
Aim for lukewarm or approximately body temperature, not hot. The FDA recommends testing a few drops before feeding. If the formula feels hot, let it cool and test it again.
Can You Warm Formula in the Microwave?
No. A microwave can heat formula unevenly. The bottle may feel cool while parts of the liquid are hot enough to burn your baby's mouth or throat. This is why both FDA guidance and product labels advise against microwave warming.
Can You Use a Bottle Warmer?
A bottle warmer can be convenient, but it is not required. Follow the warmer's instructions, keep the bottle capped, and always test the formula temperature before feeding. Do not leave a bottle sitting in the warmer or use a warmer as a storage device.
Can You Reheat Formula Twice?
Do not repeatedly warm, cool, refrigerate, and warm the same bottle. Each temperature change makes safe timing harder to track. Warm only the amount needed for the next feeding. If your baby begins drinking, discard what remains within 1 hour from the start of feeding.
How Long Is Formula Good After Warming?
Warming does not extend the formula's safe storage time. Feed the bottle promptly and follow the formula label. Once feeding begins, the CDC says to use the formula within 1 hour and throw away the remainder. If the bottle sat out before warming, the original 2-hour limit from preparation still matters.
Common Warming Mistakes to Avoid
- Microwaving the bottle.
- Using boiling water that can overheat the formula.
- Letting water enter the bottle or touch the nipple.
- Saving a bottle after your baby has started drinking.
- Warming the same bottle multiple times.
- Forgetting when the formula was prepared.
- Ignoring stricter storage directions on the formula label.
Frequently Asked Questions
How do you warm formula from the fridge?
Keep the bottle sealed and place it in warm water or hold it under warm running water for a few minutes. Swirl and test a few drops before feeding.
Can babies drink cold formula?
Yes. Formula does not need to be warmed. A safely stored refrigerated bottle can be offered cold if your baby accepts it.
Can you reheat untouched formula?
You can warm a properly refrigerated, untouched bottle once for a feeding. Check that it is still within 24 hours of preparation and follow the product label.
Can you reheat formula after the baby drank from it?
No. Once feeding begins, saliva can enter the bottle. Use or discard the formula within 1 hour from the start of feeding and do not save it for later.
Can you put warmed formula back in the fridge?
Do not cool and refrigerate a warmed feeding bottle for later use. Warm only what you need, keep track of the original preparation time, and discard leftovers after feeding.
Is a bottle warmer safer than warm water?
Both can be used when their instructions are followed. The important steps are avoiding overheating, keeping water out of the bottle, and testing the temperature before feeding.
More Formula Preparation Help
Use our Baby Formula Preparation Guides for brand-specific mixing instructions. You can also visit the CDC infant formula preparation and storage guide for current public-health recommendations.
Last reviewed: July 2026. Safety guidance checked against current CDC and FDA recommendations. This article is educational and does not replace your pediatrician's advice.