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Baby feeding amount calculator
How much milk does my baby need per day?
Australian guidance gives formula volumes per kilogram of body weight per day, and the figure declines with age: Pregnancy, Birth and Baby publishes 30 to 60 ml per kilogram per day for the first 4 days, 150 ml per kilogram from 5 days to 3 months, 120 ml per kilogram from 3 to 6 months, and 100 ml per kilogram from 6 to 12 months. A 6 kg baby at two months therefore lands near 900 ml a day, typically across 6 to 8 feeds. Breastfed babies are not measured this way — there is no published millilitre figure for a baby at the breast, and the Australian Breastfeeding Association instead publishes colostrum volumes of about 2 to 10 ml per feed on day one, rising to 30 to 60 ml by day four, alongside 8 to 14 or more feeds in 24 hours.
How much milk does my baby need?
Australian published guidance, for the way you feed. Choose one.
Commonly 6 to 8 a day at this age.
Across a whole day
about 600 ml
about 20.3 fl oz
Across 6 feeds, that is roughly
100 ml per feed
about 3.4 fl oz
How this is worked out
4 kg × 150 ml/kg/day = 600 ml a day
600 ml ÷ 6 feeds ≈ 100 ml a feed
The 150 ml/kg/day figure for 5 days to 3 months is published by Pregnancy, Birth and Baby, the Australian Government's health service, and the same bands are published by Queensland Health. Results here are rounded to the nearest 10 ml a day and 5 ml a feed. That arithmetic is the whole of what this tool does — it does not assess your baby's nutrition or growth.
If you are breastfeeding, this arithmetic does not apply — no Australian health service publishes a millilitre figure for a baby at the breast, because there is no way to measure one. Switch to the Breastfeeding tab above for what is published instead. Babies also feed unevenly across a day, so the per-feed figure is an average rather than a quota for every bottle, and Pregnancy, Birth and Baby says outright never to force a baby to finish a bottle. Babies born preterm, or with a medical or growth condition, are fed to advice from their own health professional, and that advice always overrides this.
Feeding both ways? Mixed feeding is answered in the questions below — how much formula to give alongside a breastfeed is the one figure this calculator cannot work out for you.
Baby formula chart by age
The volumes Pregnancy, Birth and Baby publishes, with each band's own worked example. Queensland Health publishes the same bands.
| Age | Per day | Feeds a day | Worked example | Notes |
|---|---|---|---|---|
| 1 to 4 days | 30–60 ml/kg/day | 6 to 8 | 5 kg ≈ 150–300 ml a day | Volumes are tiny in the first days and climb steeply. A newborn stomach holds very little. |
| 5 days to 3 months | 150 ml/kg/day | 6 to 8 | 6 kg ≈ 900 ml a day | The band most parents are in when they search. Feeds get bigger and less frequent across it. |
| 3 to 6 months | 120 ml/kg/day | 5 to 6 | 8 kg ≈ 960 ml a day | The per-kilogram figure drops as growth slows, so a heavier baby does not simply scale up. |
| 6 to 12 months | 100 ml/kg/day | 5 to 6 | 10 kg ≈ 1000 ml a day | Milk stays a main source of nutrition while solids are introduced alongside it. |
How much a breastfed newborn takes in the first days
Colostrum volumes per feed, published by the Australian Breastfeeding Association. Newborns commonly breastfeed 8 to 14 times or more in a 24-hour period.
| Age | Colostrum per feed |
|---|---|
| 1 day old | 2–10 ml |
| 1 to 2 days old | 5–15 ml |
| 2 to 3 days old | 15–30 ml |
| 3 to 4 days old | 30–60 ml |
Past the first days there is no per-feed figure for a baby at the breast, because there is no way to measure one. For planning expressed milk, the ABA publishes that exclusively breastfed babies aged 1 to 6 months drink an average of 750–800 ml over 24 hours, with some taking 500 ml and others 1000 ml or more — a spread wide enough to show why no single number describes a breastfed baby.
The maths behind the estimate
Australian guidance gives a formula-fed baby's daily intake in millilitres per kilogram of body weight, and — this is the part most charts get wrong — the figure declines as a baby grows. Pregnancy, Birth and Baby publishes 30–60 ml/kg/day for the first 4 days, 150 ml/kg/day from 5 days to 3 months, 120 ml/kg/day from 3 to 6 months, and 100 ml/kg/day from 6 to 12 months. Multiply your baby's weight in kilograms by the figure for their age band and you have the whole day; divide by the number of feeds and you have a rough per-feed figure.
Because the figure steps down with age, a baby does not simply take more per kilogram as they get heavier. Using the newborn figure at five months overstates a baby's day by a quarter; using an older figure on a newborn understates it. That is why the calculator asks for the age band as well as the weight.
Why the first week is the number to get right
The first days are where general feeding charts drift furthest from published guidance, and where a parent is least equipped to discount them. A newborn stomach holds very little: the ABA publishes colostrum volumes of 2–10 ml a feed at one day old. A chart that answers "first week" with 45–60 ml a feed is describing a baby several days older, and a parent whose newborn has just taken 7 ml reads it as a shortfall when it is the published amount.
For a formula-fed newborn, the equivalent published figure is 30–60 ml/kg/day across the first 4 days — for a 3.5 kg baby, roughly 105–210 ml across a whole day rather than per feed.
Why the per-feed number is an average, not a quota
Babies do not distribute their intake evenly. A big morning bottle followed by a small afternoon one is completely normal, and cluster feeding in the evening is common. What matters is the total across the day and the week, not any single bottle.
Forcing a baby to finish a calculated amount works against the appetite regulation they are born with. Pregnancy, Birth and Baby puts it plainly: never force your baby to finish a bottle. Paced bottle feeding — letting the baby stop when they show they are done — is the approach Australian health services recommend.
None of this answers the question parents ask next, which is whether to wake a sleepy newborn to take the feed at all. That one turns on weight gain rather than volume, and whether to set an alarm to feed a newborn sets out what published guidance says and when it stops applying.
Feeding questions parents ask
- How much formula does a newborn need in the first week?
- Far less than most charts suggest. Pregnancy, Birth and Baby publishes 30 to 60 ml per kilogram of body weight per day for the first 4 days, which puts a 3.5 kg newborn near 105 to 210 ml across a whole day — spread over six to eight feeds, that is roughly 13 to 35 ml a feed, not the 45 to 60 ml a feed some charts print. From 5 days the published figure steps up to 150 ml per kilogram per day.
- How much colostrum does a breastfed newborn take?
- The Australian Breastfeeding Association publishes colostrum volumes of about 2 to 10 ml per feed at 1 day old, 5 to 15 ml at 1 to 2 days, 15 to 30 ml at 2 to 3 days, and 30 to 60 ml at 3 to 4 days. The amounts are meant to be small — a newborn stomach holds very little, and a few millilitres a feed on day one is the published amount rather than a shortfall.
- Does the millilitres-per-kilogram figure stay the same as my baby grows?
- No, and this is where many charts mislead. Australian guidance declines with age: 150 ml per kilogram per day from 5 days to 3 months, 120 ml per kilogram from 3 to 6 months, and 100 ml per kilogram from 6 to 12 months. A heavier, older baby does not simply scale up on the newborn figure, so the age band matters as much as the weight.
- What do health services look at for a breastfed baby?
- Breastfed babies cannot be measured in millilitres, and trying to is a common source of unnecessary worry. Published guidance points to a combination of things rather than any single number: wet nappies, weight gain, the colour of wee, and how a baby is after feeds. Working out what that combination means for a particular baby is a job for your child health nurse, midwife, GP or lactation consultant — it is not something a chart or a calculator can do.
- How much formula should I give alongside breastfeeds?
- This is the one feeding question we have not put a calculator to. How much formula a baby needs alongside a breastfeed depends on how much they have already taken at the breast, and that is very difficult to measure — so a per-feed figure here would be arithmetic on a number nobody has. Pregnancy, Birth and Baby advises speaking with your maternity care provider or a lactation consultant before starting mixed feeding. They can look at your baby, your feeds and your reasons for topping up, which is what the amount actually turns on.
- Will mixed feeding affect my milk supply?
- It can, because supply follows demand — a baby who breastfeeds less prompts the breasts to make less milk. If you want to keep your supply up, Pregnancy, Birth and Baby suggests starting with small amounts and increasing gradually while continuing to breastfeed often. A lactation consultant, child health nurse, midwife or GP can help you settle on a mixed-feeding pattern that works for your family, and is the right person to ask before changing one.
- Should I wake my baby for a feed?
- Newborns are usually fed on demand, but babies who have not regained their birth weight, who were born preterm, or who are jaundiced may need waking for feeds. Follow the advice of your midwife, child health nurse or GP over any general guidance, as this is one of the areas where individual circumstances matter most.
Where these numbers come from
- Pregnancy, Birth and Baby — Feeding your baby with formula — The Australian Government health service’s published formula volumes, in millilitres per kilogram of body weight per day, banded by age from the first days to twelve months.
- Pregnancy, Birth and Baby — Bottle feeding your baby — Feeds per 24 hours by age, and responsive bottle feeding.
- Queensland Health — Infant formula feeding — Queensland Health’s formula volumes per kilogram per day, which corroborate the national age bands.
- Australian Breastfeeding Association — Expected feeds and nappies through the first week, and the colostrum volumes a newborn takes per feed day by day.
- Australian Breastfeeding Association — Exclusive expressing — Average breastmilk taken over 24 hours by babies aged 1 to 6 months.
- Pregnancy, Birth and Baby — Mixed feeding — Combining breastfeeding and formula, and the effect on milk supply.
- Raising Children Network — Bottle-feeding — Responsive bottle feeding, and why babies vary in how much they take.
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Stop doing this maths in your head
BubSync adds up feeds as you log them, so the daily total is already there when you want it — and whoever gives the next bottle can see what the baby has already had, without a text message.
