Free tool · no sign-up
ml to oz converter
Convert baby bottle and formula amounts between milliliters and ounces. Type in either box and the other updates instantly.
120 ml ≈ 4.1 oz. On bottle markings that's about 4 oz.
Common amounts
How many ml are in an ounce?
One US fluid ounce equals about 29.57 milliliters, and most baby bottles round it to 30 ml. To convert, multiply ounces by 29.57 to get ml, or divide ml by 29.57 to get ounces. So 60 ml is about 2 oz, 120 ml is about 4 oz, and 240 ml is about 8 oz.
Common baby bottle sizes in ml and oz
| Bottle | Milliliters | Often used for |
|---|---|---|
| 2 oz | 59 ml | Newborn first days, colostrum, small top-ups |
| 4 oz | 118 ml | Newborn and slow-flow bottles (many "small" bottles) |
| 5 oz | 148 ml | Common small bottle size |
| 8 oz | 237 ml | Standard large bottle for older babies |
| 9 oz | 266 ml | Common large bottle size |
| 11 oz | 325 ml | Extra-large bottle for older babies |
Bottle makers round differently, so a "9 oz" bottle may be labeled 260 or 270 ml.
How we calculate this
ml = oz × 29.5735 and oz = ml ÷ 29.5735. One US fluid ounce is defined as 1/128 of a US gallon, which is exactly 29.5735295625 ml (NIST). We show ml to the nearest 0.1 and oz to the nearest 0.01, plus the nearest half ounce you'd see on a bottle.
ml to oz chart for feeds
| ml | oz (exact) | oz (bottle marking) |
|---|---|---|
| 10 ml | 0.34 oz | 0.5 oz |
| 20 ml | 0.68 oz | 0.5 oz |
| 30 ml | 1.01 oz | 1 oz |
| 45 ml | 1.52 oz | 1.5 oz |
| 60 ml | 2.03 oz | 2 oz |
| 75 ml | 2.54 oz | 2.5 oz |
| 90 ml | 3.04 oz | 3 oz |
| 105 ml | 3.55 oz | 3.5 oz |
| 120 ml | 4.06 oz | 4 oz |
| 150 ml | 5.07 oz | 5 oz |
| 180 ml | 6.09 oz | 6 oz |
| 210 ml | 7.10 oz | 7 oz |
| 240 ml | 8.12 oz | 8 oz |
When to call your pediatrician
- Your baby regularly finishes bottles and still seems hungry, or often refuses feeds.
- You're unsure how to mix your baby's formula. Ask your pediatrician; never dilute formula to make it last.
- Fewer wet diapers than expected for your baby's age (after day 5, fewer than 6 in 24 hours), or dark yellow urine.
- A temperature of 100.4°F (38°C) or higher in a baby under 3 months. Call right away, day or night.
- Very sleepy, floppy or hard to wake for feeds, or less alert than usual.
- Refusing feeds, or several feeds in a row that are much smaller than usual.
- Signs of dehydration: dry mouth, no tears, a sunken soft spot on the head, or no poop along with very few wet diapers.
- Yellow skin or eyes that's spreading or getting deeper, especially in the first week.
- Forceful or green vomiting, or blood in the poop.
Call 911 (or your local emergency number) if your baby has trouble breathing, turns blue or gray around the lips, or won't wake up.
If something feels off, trust your gut and call. That's what they're there for.
Frequently asked questions
How many ml are in 1 oz?
One US fluid ounce is about 29.57 ml. Many baby bottles and formula labels round it to 30 ml, which is close enough for feeding. One UK (imperial) fluid ounce is slightly smaller, about 28.41 ml, so UK and US bottles can differ by about 1 ml per ounce.
How many oz is 120 ml?
120 ml is about 4.06 US fluid ounces, so you can treat it as 4 oz on a baby bottle. Other common amounts: 60 ml is about 2 oz, 90 ml is about 3 oz, 150 ml is about 5 oz, and 240 ml is about 8 oz.
How many ml is a 4 oz bottle?
A 4 oz bottle holds about 120 ml (118 ml exactly). An 8 oz bottle holds about 240 ml, a 5 oz bottle about 150 ml, and a 9 oz bottle about 260 to 270 ml. Bottles often have both scales printed on the side.
Should I measure formula in ml or oz?
Either works. Use whichever scale is printed most clearly on your bottle, and stick to it. What matters most is mixing formula exactly as the label says: the right number of level scoops for the amount of water. Adding extra water or extra powder isn't safe.
Sources
- NIST (U.S. National Institute of Standards and Technology): Unit conversion (NIST Handbook 44, Appendix C tables)(opens in a new tab)
- American Academy of Pediatrics (HealthyChildren.org): Amount and Schedule of Formula Feedings(opens in a new tab)
- Centers for Disease Control and Prevention (CDC): How Much and How Often to Feed Infant Formula(opens in a new tab)
Last reviewed: November 2026
Feedoo Baby shares general information, not medical advice. Every baby is different. If you're worried about feeding, weight gain, diapers or your baby's health, call your pediatrician, midwife or health visitor.
Log in ml, see it all add up
Feedoo Baby logs bottle volumes in ml and adds them up against an age-based daily target, so you can see the day's total at a glance.
- Two-tap bottle logging with ml amounts
- Daily intake vs age-based targets
- Stats by day, week and month: ml by feed type
- Shared with everyone who gives bottles
14 days free, no credit card. Then $24/month per baby, with unlimited caregivers.