Breast Milk Calculator
Use this breast milk calculator to estimate how much pumped milk your baby may need per bottle, per day and while you are away.
Updated October 22, 2026
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Breast Milk Amounts Are Calculated
Breast milk intake is the amount of milk your baby drinks in 24 hours. After a fast rise in the first weeks, it stays about the same from 1 to 6 months, even as your baby gains weight¹. This calculator takes the typical daily amount for your baby's age and splits it across feeds and hours.
What This Calculator Measures
It estimates a typical amount of expressed breast milk for a healthy, full-term baby from birth to 12 months. It does not measure your milk supply or tell you whether your baby is getting enough. Hunger and fullness cues and weight checks do that.
The Formula
Milk per bottle = daily amount ÷ feeds per day
Milk for time away = daily amount ÷ 24 x hours away
Typical daily amount from 1 to 6 months = about 765 mL (26 oz)
The 765 mL figure is the average of 71 exclusively breastfed babies aged 1 to 6 months, who were weighed before and after every feed for a full day².
How This Calculator Computes Your Result
Enter your baby's age in days, weeks or months. Feeds per day and hours away are optional. Breastfed babies usually feed about 8 to 12 times in 24 hours⁴, so count every bottle and breastfeed. If you leave it blank, the tool uses 10 feeds in the first month, 8 from 1 to 6 months and 6 from 6 to 12 months.
You get the amount per bottle, per day and per hour in mL and US fluid ounces (1 fl oz = 29.57 mL). Hours away adds how much milk to leave and how many bottles. CDC storage times appear with every result.
Example: a 3-month-old with 8 feeds a day takes about 765 mL (25.9 oz) a day, or 95 mL (3.2 oz) per bottle. For 10 hours away, leave about 320 mL (10.8 oz) in 3 to 4 bottles.
What Your Result Means
Your result is a typical amount, not a target. These are the amounts the calculator uses by age² ³:
Age | Typical daily amount | Typical amount per feed |
First 24 hours | Small amounts of colostrum | 2 to 10 mL |
24 to 48 hours | Rising | 5 to 15 mL |
48 to 72 hours | Rising | 15 to 30 mL |
72 to 96 hours | Rising | 30 to 60 mL |
Rest of first month | Rises from about 400 mL a day at day 5 to about 765 mL by 1 month⁸ | About 40 to 75 mL with 10 feeds |
1 to 6 months | About 765 mL (26 oz) | About 95 mL (3.2 oz) with 8 feeds |
6 to 12 months | About 620 mL (21 oz), falling as solids increase | About 105 mL (3.5 oz) with 6 feeds |
Normal intake varies a lot. In the study of 71 babies, most took about 600 to 930 mL (20 to 31 oz) a day, and the full range was 464 to 1317 mL (about 16 to 45 oz)². From 1 to 6 months, the average works out to about 32 mL (1.1 oz) for each hour of bottle feeding.
Why Formula Rules Overestimate for Breastfed Babies
The AAP rule for formula is about 2.5 ounces per pound of body weight a day, up to about 32 ounces⁷. That rule grows as your baby grows. Breast milk intake does not: when breastfed babies were followed from 1 to 6 months, feeds became fewer and larger, but total daily intake stayed constant¹.
Take a 14 lb baby at 4 months. The formula rule gives 35 oz, capped at 32 oz (about 945 mL). The breastfed average is about 26 oz (765 mL)², so the formula rule asks for about 6 oz a day more. For formula, the Baby Formula Calculator uses the AAP weight rule.
Storing Pumped Milk Safely
The CDC gives these storage times for freshly pumped breast milk⁵:
Where | How long |
Room temperature (77°F or colder) | Up to 4 hours |
Refrigerator | Up to 4 days |
Freezer | About 6 months is best; up to 12 months is acceptable |
Milk thawed in the refrigerator: use within 24 hours, counted from when it is completely thawed. Never refreeze thawed milk⁵.
Milk brought to room temperature or warmed, or left over in a bottle: use within 2 hours, then throw it away⁵.
Store milk in 2 to 4 ounces or the amount offered at one feeding. For childcare, label it with the date it was expressed and your child's name⁵.
Keep milk out of the fridge or freezer door, and do not heat it on the stove or in the microwave⁵.
An insulated cooler with frozen ice packs keeps milk for up to 24 hours when traveling⁵.
Paced Bottle Feeding
Paced bottle feeding lets your baby control the flow and stop when full. The Minnesota WIC program describes these steps⁶:
Use a small, 4 oz bottle and a slow flow nipple.
Hold your baby semi-upright, with the bottle level with the floor, tipped just enough to fill the nipple about halfway.
After 3 to 5 swallows (about 20 to 30 seconds), tip the bottle down for a short break, with the nipple still in the mouth.
Stop when your baby no longer sucks after a break, turns away or pushes the nipple away.
If your baby often seems hungry after the usual amount, or you are worried about intake, talk with your pediatrician or an International Board Certified Lactation Consultant (IBCLC). The CDC also suggests asking your baby's doctor or nurse⁴.
Typical Breast Milk per Feed by Age
How much a baby typically takes at one feed, from the first day to 12 months. Amounts rise fast in the first days, then level off.
- Typical range per feed
- Typical amount per feed
Show data table
| Age | Typical range per feed | Typical amount per feed |
|---|---|---|
| First 24 hours | 2 to 10 mL | – |
| 24 to 48 hours | 5 to 15 mL | – |
| 48 to 72 hours | 15 to 30 mL | – |
| 72 to 96 hours | 30 to 60 mL | – |
| Rest of first month, 10 feeds | 40 to 75 mL | – |
| 1 to 6 months, 8 feeds: about 95 mL | – | About 95 mL |
| 6 to 12 months, 6 feeds: about 105 mL | – | About 105 mL |
A Note on Accuracy
This calculator uses average intakes from studies that weighed breastfed babies before and after feeds, and healthy babies vary widely. First month amounts are a smooth estimate between measured points, and amounts after 6 months depend on solid food. It is not for babies born early or babies with a feeding plan from their care team.
Frequently Asked Questions
How much breast milk should a baby drink a day?
From about 1 to 6 months, a typical exclusively breastfed baby drinks about 765 mL (26 oz) a day, and most take between about 600 and 930 mL². Intake is lower in the first weeks and usually falls slowly once solid foods start².
How many ounces of breast milk should be in a bottle?
From 1 to 6 months, about 3 to 4 oz is typical. A day's milk of about 765 mL split over 7 or 8 feeds gives 3.2 to 3.7 oz (95 to 110 mL) per bottle².
How much breast milk should I send to daycare?
A simple guide from 1 to 6 months is about 1.1 oz (32 mL) for each hour you are apart². For 10 hours away, that is about 10.8 oz (320 mL), packed as 3 to 4 bottles.
How accurate is a breast milk calculator?
It uses averages from studies that weighed babies before and after every feed, but healthy babies in one study ranged from 464 to 1317 mL a day². Your baby's cues and growth are a better guide, so talk with your pediatrician or an IBCLC if you are worried.
Sources
Longitudinal Changes in Breastfeeding Patterns from 1 to 6 Months of Lactation, Kent et al., 2013
Exposure Factors Handbook, Chapter 15: Human Milk Intake, US EPA, 2011
ABM Clinical Protocol #3: Supplementary Feedings in the Healthy Term Breastfed Neonate, Revised 2017, Academy of Breastfeeding Medicine, 2017
Paced Bottle Feeding, Minnesota Department of Health WIC
Amount and Schedule of Baby Formula Feedings, American Academy of Pediatrics, 2022
Breastmilk Production in the First 4 Weeks after Birth of Term Infants, Kent et al., 2016