How Much Breast Milk Does a Baby Need? [Chart by Age]

You’re standing at the counter, holding a bottle, and you have no idea how much to put in it. The formula can has a chart. The pump doesn’t. Your mother-in-law says 6 ounces. The daycare form wants a number by Friday. And all you know is that your baby has never once told you how many ounces they just drank.

First, the part that will feel familiar: you pour 4 ounces, your baby drinks 2, and you wonder if your milk is the problem. Then the next day they gulp down 5 and you wonder if you’re starving them at the breast. You’re not doing anything wrong. Nobody gave you the breastfed numbers, and they’re very different from the formula ones.

How much breast milk does a baby need?

From about 1 month to 6 months, most breastfed babies drink around 25 ounces a day. Research on exclusively breastfed babies puts the normal range at about 19 to 30 ounces in 24 hours. Here’s the part that surprises almost everyone: that number stays about the same the whole time.

Formula-fed babies keep drinking more each month. Breastfed babies don’t, because your milk changes with them. The fat and calories in breast milk shift as your baby grows, so a 5 month old can grow just fine on about the same amount as a 6 week old.

That’s why the bottle sizes you see online, like 6 to 8 ounces at 4 months, can make you panic. Those numbers usually come from formula charts.

Breast milk chart by age

Use this as a starting point, not a rule. Every baby is a little different, and the amount changes from feed to feed and day to day.

Your baby’s stomach is tiny at birth, about the size of a cherry. It grows fast in the first two weeks. After that, the per-feed amount levels off around 3 to 4 ounces for most babies.

If you want the “how often” side of this, our baby feeding schedule by age walks through feeds month by month.

Why the amount matters (and why it doesn’t go up)

Getting the number right protects your supply and your baby’s tummy. Here’s why it’s worth knowing.

Too-big bottles can hurt your supply. If your baby drinks 7 ounces at daycare, they may nurse less in the evening. Less milk removed means your body makes less. Over a few weeks, that can shrink your supply for real.

Too-big bottles can also mean an unhappy baby. A baby who chugs a big bottle fast often spits up, gets gassy, or seems fussy right after. Their stomach was full before their brain caught up.

Knowing the real number lowers the stress. When you know 25 ounces a day is normal, a pump session of 3 ounces stops looking like a failure. Most of the worry around bottles comes from comparing breast milk to formula math.

How to figure out your baby’s bottle size, step by step

Here’s the simple way to land on a number that fits your baby.

1. Start with 25 ounces a day. That’s the average for a breastfed baby from 1 to 6 months. If your baby is under 1 month, use the chart above instead.

2. Count how many times your baby eats in 24 hours. Count every feed, day and night. Most babies this age eat 6 to 9 times.

3. Divide 25 by the number of feeds. If your baby eats 8 times a day, that’s about 3 ounces per bottle. If they eat 6 times, it’s about 4 ounces.

4. Make the first bottle a little smaller. Start with that number or half an ounce less. It’s easy to add more, and you can’t un-pour thawed milk.

5. Feed slowly with paced bottle feeding. Hold the bottle flat and let your baby pull the milk. Paced bottle feeding takes 10 to 20 minutes and lets your baby feel full before the bottle is empty.

6. Watch your baby, not the bottle. Turning away, slowing down, relaxed hands and a sleepy face mean they’re done. It’s OK to leave an ounce behind.

7. Adjust after a few days. If your baby finishes every bottle fast and still roots for more, add half an ounce. If they leave milk in most bottles, go down half an ounce.

How much breast milk to send to daycare

Plan on about 1 to 1.5 ounces for every hour you’re away from your baby. That rule works well for most babies from about 1 month to 6 months.

Here’s what that looks like for common workdays:

• 8 hours away: about 8 to 12 ounces, in 3 bottles
• 9 hours away: about 9 to 13 ounces, in 3 to 4 bottles
• 10 hours away: about 10 to 15 ounces, in 3 to 4 bottles

Send bottles of 3 to 4 ounces, plus one small 1 to 2 ounce “top up” bottle. Small bottles mean less wasted milk if your baby isn’t very hungry.

Ask your caregiver to use paced feeding. Many daycares are used to formula babies and feed quickly. If your baby is drinking much more at daycare than this rule suggests, the speed of the bottle is usually the reason, not hunger.

And it’s normal if your baby drinks less while you’re gone, then makes up for it nursing in the evening and at night. Some babies do this on purpose. It’s called reverse cycling, and it’s fine as long as diapers and weight look good.

Need help building that daycare stash? Our guide to storing breast milk covers how long it lasts in the fridge and freezer.

Why your pump output doesn’t match these numbers

Your pump output is not a measure of your milk supply. This one trips up so many moms.

If you nurse and pump, it’s normal to get 0.5 to 2 ounces total from both sides in one session. Your baby already took most of the milk. A pump is also much less efficient than a baby who is latched well.

If you exclusively pump, you’ll usually see more per session, since the pump is doing all the work. Most moms who exclusively pump aim for that same 25 to 35 ounces a day. Our exclusive pumping schedule breaks down how to get there.

The amount also shifts by time of day. Many moms pump the most in the early morning and the least in the late afternoon. That’s normal too.

Signs your baby is getting enough breast milk

Count diapers and watch weight. That tells you more than ounces ever will.

• Wet diapers: at least 6 heavy wet diapers a day after day 5
• Poops: at least 3 to 4 yellow poops a day in the first 6 weeks (older babies may go less)
• Weight: back to birth weight by about 2 weeks, then gaining roughly 5 to 7 ounces a week for the first few months
• Mood: content for a while after most feeds, alert when awake

If those look good, your baby is getting enough, no matter what the bottle says. Our post on signs your baby is getting enough milk goes deeper on each one.

When the amount changes

Some days your baby will want more, and that’s normal.

• Growth spurts: around 2 to 3 weeks, 6 weeks, 3 months and 6 months, babies often want extra feeds for a few days. Feed more often instead of making bottles much bigger.
• Cluster feeding: many babies bunch feeds together in the evening. That’s normal and it doesn’t mean your milk ran out.
• Starting solids: around 6 months, solids start, but breast milk stays the main food until about 12 months. Milk drops slowly, not all at once.
• Sick days: a baby with a cold may eat less per feed but more often. Watch diapers closely.

When to call your pediatrician

Call your baby’s doctor if you notice any of these:

• Fewer than 6 wet diapers a day after day 5, or dark yellow pee
• No poop for more than a day in the first 6 weeks
• Not back to birth weight by about 2 weeks
• Your baby seems very sleepy and hard to wake for feeds
• Your baby regularly drinks far more than 32 ounces a day and still seems hungry
• Forceful or green vomiting, or spit up with blood
• Signs of dehydration: dry mouth, no tears, a sunken soft spot on the head

Trust your gut. If something feels off, it’s always OK to call.

The thing I wish I’d known

I wish someone had told me that breastfed babies don’t follow the formula chart. I spent weeks thinking my baby was “behind” because she took 4 ounces when the internet said 6. She was growing right on her curve the whole time.

You don’t have to measure every drop to be a good mom. At the breast, your baby has been deciding how much to drink since day 1, and they’ve been pretty good at it. Bottles just make the number visible.

So here’s your next step. Take 25, divide it by how many times your baby eats, and make your next bottle that size. Feed it slowly. Watch your baby, not the lines on the bottle. Then let yourself stop doing the math.