Bottle & formula
Formula vs breast milk amounts: why the numbers differ
Last reviewed November 2026 against AAP, CDC, NHS and WHO guidance · Sources
Quick answer
Formula amounts climb with age, from about 1–2 oz (30–60 ml) per feed in week 1 to 6–8 oz (180–240 ml) at six months, up to about 32 oz (960 ml) a day (AAP). Breast milk intake levels off at about 750 ml (25 oz) a day from 1 to 6 months (HSE), so breast milk bottles stay smaller.
- Breast milk, 1–6 mo
- ~750 ml (25 oz)/day
- Formula ceiling
- ~32 oz (960 ml)/day
- EBM bottle
- Often 3–5 oz
On this page
How much formula vs breast milk does a baby need?
| Age | Formula per feed | Breast milk per bottle | Breast milk per day |
|---|---|---|---|
| 1-week-old | 1–2 oz (30–60 ml) | 0.5–2 oz (15–60 ml) | Rises fast: HSE lists 0–123 ml on day 1 and 98–775 ml by day 3 |
| 2-week-old | 2–3 oz (60–90 ml) | 2–3 oz (60–90 ml) | Roughly 16–25 oz (480–750 ml), climbing toward the 1–6 month level |
| 4-week-old | 3–4 oz (90–120 ml) | 3–4 oz (90–120 ml) | About 700–900 ml (23.5–30 oz) from around 4–5 weeks |
| 8-week-old | 4–5 oz (120–150 ml) | 3–5 oz (90–150 ml) | About 750 ml (25 oz) |
| 12-week-old | 4–6 oz (120–180 ml) | 3–5 oz (90–150 ml) | About 750 ml (25 oz) |
| 3-month-old | 5–6 oz (150–180 ml) | 3–5 oz (90–150 ml) | About 750 ml (25 oz) |
| 4-month-old | 5–7 oz (150–210 ml) | 3–5 oz (90–150 ml) | About 750 ml (25 oz) |
| 5-month-old | 6–7 oz (180–210 ml) | 3–5 oz (90–150 ml) | About 750 ml (25 oz) |
| 6-month-old | 6–8 oz (180–240 ml) | 4–6 oz (120–180 ml) | Around 750 ml (25 oz), easing as solids grow |
Why do breastfed babies drink less from a bottle?
Breast milk changes with your baby's needs and is digested easily, and breastfed babies regulate how much they take at the breast. Once supply is established, the HSE says babies aged 1 to 6 months take about 750 ml a day from breast milk alone, a number that stays fairly steady.
Formula guidance works differently. The AAP describes formula intake rising about 1 oz per feed each month until it levels off around 7–8 oz per feed, with the daily total capped near 32 oz.
How big should a bottle of breast milk be?
A simple method: divide about 750 ml (25 oz) by the number of feeds your baby has in 24 hours. With 8 feeds, that's about 95 ml (3 oz) per bottle. With 6 feeds, about 125 ml (4 oz).
Leave a small extra bottle (1–2 oz) for hungry days, rather than one giant bottle that may go to waste. The CDC says leftover breast milk from a feed should be used within 2 hours.
How do I size bottles when combo feeding?
- Count breastfeeds and bottles together toward the day's feeds.
- Formula bottles for a combo-fed baby are often smaller than the full formula chart, since breastfeeds cover part of the day.
- Use paced bottle feeding so your baby sets the pace for both.
- Diapers and growth tell you whether the mix is working.
When to call your pediatrician
- A rectal temperature of 100.4°F (38°C) or higher in a baby 3 months or younger. The AAP says to call right away, even if your baby seems otherwise well.
- Fewer wet diapers than expected for their age (fewer than 6 a day from about day 5), or dark yellow urine.
- Very sleepy and hard to wake for feeds, floppy, or unusually quiet.
- Refusing feeds, or feeding poorly several times in a row.
- Signs of dehydration: dry mouth, no tears, or a sunken soft spot on the head.
- Forceful or green vomiting, or vomiting after most feeds.
- Red, black (after the first meconium poops) or white/pale gray poop.
- Yellow skin or eyes that spread or deepen, or any yellow color in the first 24 hours.
- Trouble breathing, blue or gray lips, or your baby is limp or very hard to wake: call 911 (or your local emergency number) now.
If something feels wrong, trust that feeling and call. You never need a reason beyond worry.
Questions parents ask
Do breastfed babies need as much milk as formula-fed babies?
Breastfed babies often take less by volume. The HSE says babies aged 1 to 6 months who only have breast milk take about 750 ml (25 oz) a day, while formula intake can rise toward the AAP ceiling of about 32 oz (960 ml).
How much expressed breast milk should I put in a bottle?
Divide about 750 ml (25 oz) by your baby's number of feeds a day. With 8 feeds that's about 3 oz (95 ml) per bottle. Start there and adjust to your baby's cues.
Can I mix breast milk and formula in the same bottle?
Many families do, but prepare the formula with water exactly as the label says first, then add breast milk. Never use breast milk to mix formula powder. If you're unsure, ask your pediatrician.
Why does my breastfed baby refuse a big bottle?
Probably because they don't need it. Breastfed babies often stop at 3–4 oz (90–120 ml) because that's what they usually take at the breast. Watch fullness cues and offer more only if they still seem hungry.
Related guides
- Paced bottle feeding, step by stepHow to pace a bottle feed: positioning, a horizontal bottle, breaks every few sucks and fullness cues. Works for breast milk and formula, and for every caregiver.
- Baby feeding chart by age: ounces and mlA baby feeding chart from week 1 to 12 months: ounces and ml per feed, feeds per day and daily totals for formula and breast milk, with sources.
- How to tell if your baby is getting enough breast milkSigns a breastfed baby is getting enough: wet and dirty diapers by day, weight gain, swallowing and contentment after feeds, plus the warning signs to act on.
- How much should a 3-month-old eat?How much a 3-month-old eats: 5–6 oz (150–180 ml) per feed, 5–6 times a day. Daily totals, a sample schedule, hunger cues and when to call the doctor.
Free tools
Sources
Last reviewed November 2026. Numbers are ranges from these public health sources; 1 oz ≈ 30 ml.
- HSE (Ireland's public health service): How much breast milk to express
- AAP · HealthyChildren.org: How Much Formula Does My Baby Need?
- AAP · HealthyChildren.org: Amount and Schedule of Formula Feedings
- CDC: How Much and How Often to Feed Infant Formula
- CDC: Proper Storage and Preparation of Breast Milk
- La Leche League International: Bottles and Other Tools
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.