Baby Milk Intake Calculator

A starting point, not a target

If you are here at three in the morning trying to work out whether your baby has had enough, here is the short version before anything else: the number this tool gives you is a planning estimate, not a quota. Babies are not machines with a fuel tank. They take more on some days and less on others, and both are normal.

What the calculator is genuinely good for is the first bottle of a new stage, when you have no idea whether to make 60 ml or 150. It gives you a sensible place to start so you are not guessing blind, and a rough daily total to sanity-check against. That is a real job and it does it well.

What it cannot do is tell you whether your baby is getting enough. That answer does not live in a calculator. It lives in wet nappies, in the weight chart, and in whether your baby seems content, and the sections below cover all three, because they matter more than any number on this page.

The rule underneath it: millilitres per kilo

Every guideline on this works the same way. Bigger babies need more milk, so the amount is set per kilogram of the baby, per day:

Milk per day = baby's weight in kg × millilitres per kilo per day

Then divide by however many feeds your baby takes in 24 hours to get a per-feed figure. That is the whole calculation.

The rate is the interesting bit, and it drops as your baby grows. That surprises people, because surely a bigger baby needs more? They do in total, just not proportionally. A newborn is growing at a ferocious rate relative to their size and running on milk alone. By nine months, growth has slowed and solid food is carrying part of the load, so the milk rate per kilo comes down even though the daily total may not.

What the tool assumes at each age

These are the rates behind each option in the dropdown:

You can enter weight in kilograms or pounds; the tool converts pounds for you before doing the sum, so use whichever your scales speak.

A worked example

Take a two-month-old weighing 5 kg, feeding 7 times a day. That puts them in the 1 to 3 months band, so 150 ml per kilo:

Per day = 5 × 150 = 750 ml
Per feed = 750 ÷ 7 ≈ 107 ml

So roughly 107 ml a bottle, seven times a day. In practice that will not be how it goes. One feed will be 150 and the next will be 60, and your baby will drain the bottle at 6pm and refuse it at 9pm. The 750 is the shape of the day, not a schedule. If they take 690 one day and 810 the next, nothing is wrong.

Why the first week is not a number

This one deserves a stop, because it is the one place where the honest answer is that we will not give you a figure.

Pick the first week and the tool declines. It does not estimate, it does not offer a range, it tells you to talk to your midwife or health visitor. That is deliberate, and it is worth explaining why, because a calculator that refuses to calculate looks broken until you see the reason.

Intake in the first days is not a rate. It is a ramp. A brand new baby has a stomach about the size of a cherry and takes tiny volumes of colostrum. Then milk comes in, the stomach stretches, and intake climbs steeply day by day, roughly along the lines of 60 millilitres per kilo on day one, 80 on day two, 100 on day three, 120 on day four, and 150 from about day five. By the end of the first week it has more than doubled.

There is no single millilitres-per-kilo figure that describes that week. Any number a weight-based planner picks is wrong for most of the days in it, and wrong in whichever direction is unhelpful: too low and you are underfeeding a newborn, too high and you are pushing volumes past a stomach that cannot take them. This is also the week when a baby is weighed most often and watched most closely by people who are physically present. That is the right instrument for the job, and it is not us.

An earlier version of this tool did offer a newborn figure of 60 alongside a separate option for under one month at 180. Those two describe the same baby and differ threefold, and a parent of a three-week-old picking the first would have been told to feed a third of what their baby needed. The 60 was really a day-one number wearing a month-long label. It has been removed rather than relabelled, because the underlying problem was that the first week does not fit the model at all.

One more sanity check while you are here. The 180 rate for the rest of the first month is at the top of the published range, so on a bigger baby it can produce a daily total above what paediatric guidance suggests, which caps out around 960 ml in 24 hours for most babies. If the tool hands you a number well past that, treat it as a sign the age band is wrong for your baby rather than a goal to chase.

If your baby feeds at the breast, this is not really your tool

Worth being direct about, because it is the single most common way a feeding calculator does harm.

A baby nursing directly at the breast regulates their own intake. They take what they need and stop. Nobody is measuring millilitres, and nobody should be. The markers that matter for a breastfed baby are how often they feed, usually 8 to 12 times in 24 hours in the early weeks, and what comes out the other end. Trying to hit a calculated volume at the breast is not just impossible, it is a fast route to anxiety over a number that was never measurable in the first place.

Where the arithmetic does apply is bottles. If you are feeding formula, or expressing and giving breast milk in a bottle, these rates work exactly the same for both. Expressed breast milk is milk; the volumes are the volumes.

If you are combination feeding, the honest answer is that you cannot cleanly account for the breast side, so use the tool for the bottles and let your baby's cues and growth handle the rest.

The signs that actually tell you it is working

This is the section to keep if you forget everything else on this page. You do not assess feeding from a calculator. You assess it from the baby, and the signals are unglamorous and reliable:

• Wet nappies. Around six a day from a few days after birth, wet with pale or clear urine, or feeling heavy. This is the most dependable hydration signal there is, at any age or weight.
• Dirty nappies. After the first sticky dark days, expect pale yellow or yellowish-brown, at least one a day in the early weeks.
• Weight. Babies normally lose a little in the first days and should be back to birth weight by around two weeks, then gain steadily. Healthy babies are typically weighed at birth, again in the first week, then around 8, 12 and 16 weeks, and at a year. That curve tells you more than any single day's intake.
• Contentment. A baby who settles reasonably after feeds and is alert and rousable when awake is a baby getting what they need.

If those four are in order, your baby is fine, even if the daily total looks nothing like the number this page gave you. And if they are not in order, no amount of hitting the calculated volume makes up for it.

Never make a baby finish a bottle

The risk with a number on a screen is that it starts to feel like a target, and the bottle starts to feel like homework. It is worth resisting that early.

Babies come with working appetite regulation. They stop when they are full, and a baby who is repeatedly encouraged past that point learns to ignore their own fullness signals, which is the mechanism behind overfeeding. Feeding little and often, and leaving milk in the bottle, is normal behaviour rather than a problem to solve.

A few things that help:

• Feed to cues, not the clock. Rooting, sucking on hands, mouthing. Crying is a late hunger sign, so catching the earlier ones makes feeds calmer for both of you.
• Pace the feed. Hold the bottle more horizontally and pause now and then by lowering it or slipping the teat out. Those pauses let your baby's stomach and brain catch up with each other so fullness actually registers.
• Watch for the stop signals. Slowing down, milk spilling from the sides, turning away, going fidgety or distracted. That is a baby saying they are done, and done is done.
• Never top up to reach the number. If they left 40 ml, they left 40 ml.

When to stop calculating and call someone

A calculator is the wrong tool for a worry. Contact your health visitor, midwife, GP or paediatrician rather than adjusting volumes yourself if:

• Fewer than six wet nappies a day once your baby is past day five.
• Your baby has not regained their birth weight by about two weeks, or weight gain has stalled.
• They are unusually sleepy, floppy, or hard to wake for feeds.
• Signs of dehydration: a dry mouth, no tears, a sunken soft spot, or very dark urine.
• They drain every bottle and still seem hungry, consistently, over days rather than during one growth spurt.
• Feeding is persistently distressing for either of you.

Two situations deserve a special mention. Premature babies need an individual feeding plan from their medical team, not a standard rate off a dropdown, because their needs differ substantially and often change week to week. And babies with medical conditions affecting growth or feeding are in the same category. If that is you, please use your team's numbers and treat this page as background reading only.

Finally, the practical bit no calculator covers: make formula exactly as the tin directs, never adding extra powder or extra water, and never add anything else to a bottle. Getting the concentration wrong is a genuine risk, and the tin's instructions beat any general guidance including this page.

Questions people ask

How much milk does a 5 kg baby need per day?

Around 750 ml, if they are between one and three months old, since that stage runs at about 150 ml per kilo per day. Across seven feeds that is roughly 107 ml a bottle. Treat it as a starting figure: some feeds will be much bigger and some much smaller, and the daily total will wander from day to day.

Does this work for expressed breast milk?

Yes. The volumes are the same whether the bottle holds formula or expressed breast milk. What the rates do not apply to is a baby feeding directly at the breast, where intake is not measured and does not need to be.

What if my baby wants more than the calculated amount?

Usually that is fine and normal, especially during a growth spurt, when appetite can jump for a few days and then settle. The rate is a population average and your baby is not average, they are yours. What is worth mentioning to a health visitor is a persistent pattern over days or weeks, rather than one hungry evening.

My baby is three days old. Should I choose "Newborn" or "Less than 1 month"?

Newborn. That option is built for roughly the first four days, when volumes are small and your baby's stomach is tiny. From about day five, when your milk is in and intake climbs sharply, switch to the "Less than 1 month" option. The two rates differ by three times, so picking the right one matters.

How many feeds a day should I enter?

Whatever your baby actually does, not a target. Newborns commonly feed 8 to 12 times in 24 hours, dropping to roughly 6 to 8 by two or three months and 5 to 6 by around six months. The tool divides your daily total by whatever you enter, so entering your real count gives you a realistic bottle size.

Do I keep using this once solids start?

You can, and the rate drops for exactly that reason: solids gradually take over part of the diet. But milk remains the main source of nutrition for the whole first year, so it does not fall away quickly. Once solids are properly under way, feeding stops being a volume calculation anyway, and your health visitor or paediatrician is the better guide.

References

Where the figures come from. The rate of roughly 150 to 200 ml per kilogram per day after the first week, the guidance on wet and dirty nappies as the signal of adequate intake, the weighing schedule, and the advice to feed responsively rather than to a schedule all come from the NHS guidance on formula feeding. The weight-based intake figure, the per-feed amounts in the first weeks, and the recommended upper limit of around 960 ml in 24 hours come from the American Academy of Pediatrics.

1. National Health Service (UK). Formula milk: common questions. nhs.uk
2. American Academy of Pediatrics. Amount and Schedule of Baby Formula Feedings. HealthyChildren.org. healthychildren.org