How Much Expressed Milk Should I Put in a Bottle?

The first days: much less than you think

The HSE publishes figures for the first days that are worth having in front of you before you pour anything into a bottle. For healthy full-term babies, expected amounts at a feed are a few drops to about 5ml on day one, 5–15ml on day two, and 15–30ml on day three. A newborn's stomach is small and colostrum is concentrated. A 60ml bottle offered on day two is not a target; it is a misunderstanding of the scale.

After the first month: 60 to 120ml, and it stays there

This is the fact that surprises everyone, and it is genuinely useful. Breastfed babies take roughly the same daily volume of milk from around one month until they start solids at about six months. La Leche League GB puts it directly: milk production reaches close to peak by around ten days, by about a month most people are making as much milk as their baby will ever need, and babies need about the same amount of milk each day from one to six months.

The Academy of Breastfeeding Medicine's storage protocol says the same from the practical end: it is typical for infants in daycare to take 60–120ml (2–4 ounces) of human milk at one feeding, and recommends storing in small increments such as 15–60ml to prevent waste.

So a bottle for a five-month-old is not much bigger than a bottle for a two-month-old. Milk gets more energy-dense as feeds space out; it does not need to get bigger.

A rough way to work it out

Total daily intake for an exclusively breastfed baby is commonly around 750–900ml in 24 hours. Divide by the number of feeds your baby actually takes to get a per-feed figure. A baby feeding eight times lands near 100ml; a baby feeding twelve times lands near 70ml. Both are normal. This is a starting point for filling a bottle, not a quota to meet.

Why breast milk does not scale like formula

Formula guidance uses charts based on weight, and volumes rise steadily with age. Breastfed babies do not follow that curve, because breast milk changes in composition as the baby grows while formula does not. Applying a formula chart to expressed breast milk almost always produces a bottle that is too big, which leads to overfeeding, wasted milk, and the mistaken conclusion that your supply is insufficient.

Start small, top up

• Offer 60ml first. Have a second small container ready rather than filling one large bottle.
• Store in small amounts. Thawed milk that is not used has to be thrown away.
• Once your baby has drunk from a bottle, the clock is short. The NHS says use it within one hour and discard the rest; the CDC allows two hours.

Pace the feed

The HSE's advice on giving expressed milk is specific: use a teat that allows the milk to flow out slowly so your baby can pace the feed and control how much they take, watch your baby for cues, and do not force them to finish the bottle if they do not want to. Hold the bottle roughly horizontal, let your baby draw the milk rather than pouring it in, and pause when they pause. A baby who is not being pushed to finish rarely takes far more than they need.

A bottle that empties in three or four minutes is flowing too fast. Fast bottles teach a baby to expect a flow no breast can match, and they are one of the more common routes into bottle preference.

How much to leave for a whole day away

La Leche League GB's guidance on leaving your baby is the practical one: work from how many feeds your baby would normally take in the time you are away, not from a total daily figure. If you are gone for eight hours and your baby usually feeds every three hours, that is two to three feeds, so two to three small bottles plus one spare. Carers almost always ask for more than the baby needs; agreeing the plan in advance saves both milk and argument.

If you are away for a working day, expressing at roughly the times your baby would feed protects your supply as well as producing the milk for the next day.

When bigger bottles are actually needed

If your baby is regularly finishing every bottle, still cueing to feed, and their weight gain has faltered, that is worth checking rather than simply increasing volumes. Equally, a baby who suddenly wants far more from a bottle may be being fed too fast rather than being hungrier. Ask your health visitor, public health nurse or an infant feeding team.

Wet nappies and weight, not millilitres

The measure of whether a baby is getting enough is nappies, weight gain over time and how they seem — not the number on the side of a bottle. Bottles give an illusion of precision that breastfeeding never offered, and for a lot of parents that number becomes a source of anxiety rather than reassurance. If your baby is growing along their own line and producing plenty of wet nappies, the bottle volume is right, whatever it says.

Talking to whoever is doing the feed

Most over-feeding of expressed milk happens because a carer is trying to be helpful. Agree in advance what a normal feed looks like: the size to start with, that the bottle does not need finishing, and what to do if your baby seems hungry afterwards — usually offer a little more from a second container rather than assume the plan was wrong. Writing it down for a nursery or childminder is worth the two minutes, because expressed milk is hard to replace.

Cues that a feed is finished

• Slowing down, longer pauses, and letting the teat sit in the mouth without sucking.
• Turning the head away, or pushing the bottle out with the tongue.
• Relaxed hands and body — clenched fists at the start, open palms at the end.
• Falling asleep calmly rather than fighting the bottle.

A baby who drains every bottle and immediately falls asleep may have been fed too fast rather than been very hungry.