Baby feeding amount calculator
Enter your baby's weight and age and this tool gives the typical daily and per-feed formula volume in both millilitres and fluid ounces, using the guidance body that applies where you are. For a breastfed baby it deliberately gives no number at all, because breastfed babies are fed responsively rather than to a volume. It works entirely in your browser.
Baby feeding amount calculator
No sign-up · PrivateVolumes change with age far more than most people expect — Australian guidance drops from 150 to 100 ml per kilo across the first year.
Their most recent weight, not their birth weight. Formula volumes scale with weight; breast milk volumes do not, which is why this field only appears for formula.
Only if you are working in pounds and ounces. 7 lb 11 oz means 7 in the box above and 11 here.
They genuinely differ. For a 6 kg four-month-old the UK figure and the Australian figure are nearly 500 ml a day apart. Pick the one your health service follows rather than the biggest number.
Leave blank and the tool uses the typical count for your baby's age. Fill it in with what actually happens and the per-feed figure becomes yours rather than an average.
Fill in the fields above to see your result.
Nothing you type leaves your device. The whole calculation runs in your browser.
How this is calculated
FormulaHow feeding amounts are calculated
How much milk a baby takes depends entirely on what is in the bottle, so this tool forks on that first rather than apologising for it in a footnote.
Formula: a rate multiplied by weight
For a formula-fed baby the arithmetic is two lines:
- daily volume = weight × the published millilitres per kilogram per day
- per feed = daily volume ÷ feeds in 24 hours
The rate is not one number worldwide. It is three, and for the same baby they disagree by hundreds of millilitres a day, so the tool names whose figure it is using and never averages them.
United Kingdom — 150 to 200 ml per kilogram per day, flat, from the end of the first week to six months. The wording is “By the end of their first week, most will need around 150 to 200ml per kilo of their weight a day until they’re 6 months old.” Worth knowing where that comes from: this figure is not on the current nhs.uk bottle-feeding pages, which give no ml/kg figure at all. It is published by NHS 111 Wales and repeated by NHS trusts, and that is where this tool cites it from.
Australia — age-banded, and it steps down. Pregnancy, Birth and Baby (healthdirect) publishes: 1 to 4 days, 30 to 60 ml/kg/day; 5 days to 3 months, 150 ml/kg/day; 3 to 6 months, 120 ml/kg/day; 6 to 12 months, 100 ml/kg/day. Better Health Channel (Victoria) agrees except in the last band, where it says “between 90 and 120 ml”. The tool shows 90 to 120 for that band so neither source is misquoted.
United States — stated per pound, not per kilogram. The American Academy of Pediatrics says “On average, your baby should take in about 2½ ounces (75 mL) of infant formula a day for every pound (453 g) of body weight”, with a ceiling: “Your baby should usually drink no more than an average of about 32 ounces (960 mL) of formula in 24 hours.”
The disagreement is the useful part
Take a 6 kg four-month-old. The UK rule gives 900 to 1200 ml a day. The Australian rule gives 720 ml. The AAP rule gives about 978 ml. That is a spread of nearly 500 ml a day for one baby, and the top of the UK range is above the AAP’s stated 24-hour ceiling of 960 ml. That is not an arithmetic fault. It is what happens when a flat per-kilogram rule meets a bigger baby, and the tool flags it and tells you to check with your health visitor, GP or paediatrician rather than printing the larger number and looking away.
By contrast, a 3.5 kg two-week-old comes out at 525 to 700 ml a day on the UK rule (17.8 to 23.7 fl oz), 525 ml on the Australian rule, and about 570 ml on the AAP rule — close agreement. The rules diverge as the baby grows, not at the start.
Feeds in 24 hours
These are descriptions of what babies do, not targets to hit. First week: at least 8 feeds in 24 hours (AAP). To one month: roughly every 3 to 4 hours, about 7 (AAP). One to three months: about 6. Three to six months: around 5 to 6 bottles in 24 hours (Pregnancy, Birth and Baby). Six months and over: “6 to 8 ounces (180–240 mL) at each of 4 or 5 feedings in 24 hours” (AAP). You can override the count with what actually happens in your house, which turns the per-feed figure from an average into yours.
Breastfeeding: why this tool gives no number, and why that is the right answer
The millilitres-per-kilogram arithmetic is a rule for infant formula. It is not a target for a breastfed baby, and treating it as one does real harm. A parent who believes their baby must reach a daily figure starts topping up; topping up reduces demand at the breast; reduced demand reduces supply. The number quietly destroys the thing it was meant to protect. So the breastfeeding mode of this tool produces no volume at all — not a smaller one, not a softer one, none. It gives the cue-based answer and the signs that actually indicate a baby is getting enough: 6 to 8 wet nappies a day, 2 soft yellow stools, and steady weight gain.
Unicef UK Baby Friendly: “Responsive breastfeeding involves a mother responding to her baby’s cues, as well as her own desire to feed her baby. Crucially, feeding responsively recognises that feeds are not just for nutrition, but also for love, comfort and reassurance between baby and mother.” And therefore: “breastfeeds can be long or short and at varying times in the day, depending on why the mother and her baby have decided to feed.” Unicef also states that “It is important that mothers are aware that their baby cannot be overfed or ‘spoiled’ by ‘too much feeding’.”
The belief that a normal pattern is a feed every three hours, or 8 to 10 feeds a day, is listed by Unicef UK as a common misunderstanding to be corrected in staff training — not as guidance. This tool does not restate it as guidance either. Unicef is explicit about the consequence: “Limiting feeds to fit into this routine can also threaten the mother’s milk supply, and reduces the chances of successful ongoing breastfeeding.”
Expressed breast milk gets its own mode, and its own arithmetic
Expressed milk needs a volume, but it must not use the formula rule. The AAP is the only body consulted that publishes breastfed volumes, and it publishes them per feed and flat: most breastfed infants take about 1 fl oz a feed in the first few weeks, an amount that increases slowly and “tops out at roughly 4.5 oz at a year of age”. So this tool interpolates along that line and deliberately ignores your baby’s weight. Breast milk intake does not scale with weight the way formula does. Applying the 150 to 200 ml/kg rule to expressed milk would tell you to express far more than your baby needs and tell you your supply was failing when it was not.
Unicef UK is also clear that a bottle cannot be fully responsive: “Although true responsive feeding is not possible when bottle feeding, as this risks overfeeding, the mother-baby relationship will be helped if mothers are supported to tune in to feeding cues and to hold their babies close during feeds.” Its responsive bottle feeding leaflet contains no volume figures at all — that is deliberate: “Your baby will know how much milk they need at each feed. Forcing your baby to finish a feed can be a stressful experience and can mean your baby takes more than they need.”
Fluid ounces are not one unit
A US fluid ounce is 29.5735 ml. A UK imperial fluid ounce is 28.4131 ml — about 4% smaller. The fl oz figures here are US fluid ounces, because that is the unit the AAP states its numbers in and the unit US bottles are marked in. On a UK bottle the same milk reads slightly differently. The millilitre figure is the one that never moves, so it is always given first.
What outranks this calculator
The instructions on your formula tin, because different formulas are made up to different concentrations. And your baby. The NHS: “All babies are different. Your baby will know how much milk they need… Feed your baby when they seem hungry and do not worry if they do not finish the bottle. Do not force them to take more milk than they want during a feed.”
The question behind the question
Almost nobody arrives at a feeding calculator because they are curious about arithmetic. They arrive because a baby finished a bottle and cried, or did not finish a bottle at all, or fed for forty minutes and then wanted more twenty minutes later, and somewhere underneath is the question: is my baby getting enough?
For a formula-fed baby, a number helps. You are pouring a measured volume into a bottle, so having a sense of the range is genuinely useful — it tells you whether the day you have just had was ordinary.
For a breastfed baby, the same number does damage, and this is worth being precise about rather than vague.
Why we will not give a breastfed baby a target
Milk supply works on demand. What is taken out is what gets made. If you decide your baby “should” be having 700 ml a day, and you cannot see how much they took at the breast, the only way to feel certain is to add a bottle. That bottle displaces a feed. The displaced feed is milk not removed. Milk not removed is milk not made. A week later there is genuinely less, and the number that was supposed to reassure you has become evidence that something is wrong.
This is not a fringe concern. Unicef UK Baby Friendly lists the belief that a “normal” feeding pattern is every three hours, or 8 to 10 times a day, as a misconception that has to be corrected in professional training — because it is that persistent and that harmful. So the breastfeeding mode of this tool answers the question with “there is no number” and then tells you what to look at instead.
What to look at instead
Nappies, stools and weight. Six to eight wet nappies a day, two soft yellow stools, steady weight gain. Those are observable, they do not require a scale in your kitchen, and they are what a health visitor or paediatrician will look at too. If any of them worries you, that is a conversation with a person — a midwife, health visitor, lactation consultant or GP — not an arithmetic problem. A calculator cannot weigh your baby.
The thing formula parents are rarely told
The guidance you were given depends on where you live, and the differences are not small. The UK figure is flat all the way to six months. The Australian figure steps down from 150 to 120 to about 100 millilitres per kilogram as the baby grows. Run a healthy 6 kg four-month-old through both and you get 900 to 1200 ml under one and 720 ml under the other.
Neither is wrong. They are the same evidence read with different safety margins, and both are averages across thousands of babies rather than a prescription for yours. Which is the real reason the per-feed figure this tool prints is described as an average and not a portion size: real feeds are uneven. A big one, then a small one, then a big one. As the NHS puts it, “Having a big feed does not mean your baby will go longer between feeds.”
The number that should make you pause
If this tool tells you the top of your range is above 960 ml a day, it will say so loudly. That is the AAP’s stated ceiling — “no more than an average of about 32 ounces (960 mL) of formula in 24 hours” — and a per-kilogram rule applied to a larger baby will cross it. It is not a reason to panic. It is a reason to have the conversation, and to remember that from around six months solid food starts taking over anyway.
Sources
- Infant formula: common questions — the 150 to 200 ml per kilo per day figure — NHS 111 Wales, accessed
- Bottle feeding advice — NHS, accessed
- Amount and Schedule of Baby Formula Feedings — 2½ ounces per pound per day, and the 32 ounce (960 mL) daily ceiling — American Academy of Pediatrics (HealthyChildren.org), accessed
- How Often and How Much Should Your Baby Eat? — American Academy of Pediatrics (HealthyChildren.org), accessed
- Responsive Feeding: supporting close and loving relationships (infosheet) — Unicef UK Baby Friendly Initiative, accessed
- Infant formula and responsive bottle feeding: a guide for parents — Unicef UK Baby Friendly Initiative and First Steps Nutrition Trust, accessed
- Bottle feeding your baby — the age-banded ml per kg per day table — Pregnancy, Birth and Baby (healthdirect Australia), accessed
- Bottle feeding — nutrition and safety — Better Health Channel, Department of Health, State Government of Victoria, accessed
- Infant formula factsheet — the formula tin instructions are a guide only — Sydney Children's Hospitals Network, accessed
- Formula feeding — the wet nappies and stools adequacy check — Nottinghamshire Healthcare NHS Foundation Trust, accessed