Unlike formula intake, breast milk intake stays fairly constant from about 1 month to 6 months, because breast milk changes composition as the baby grows. This helps parents and carers prepare bottles of expressed milk.
How to use the Breast Milk Intake Calculator
- Age
- Feeds per day
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter your baby’s age and how many feeds a day.
Inputs explained
| Field | What to enter |
|---|---|
| Age | Units: months, years, weeks |
| Feeds per day | A number |
Example values
How the main result changes when Age changes and everything else stays at the example values above:
| Age (months) | Breast milk per day (mL) |
|---|---|
| 1.5 | 800 |
| 2.25 | 800 |
| 3 | 800 |
| 3.75 | 800 |
| 4.5 | 800 |
| 6 | 800 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Days 1–7: about 30–60 mL per feed, rising daily
1–6 months: about 750–1,035 mL per day (average ≈ 800 mL)
Per bottle = daily amount ÷ feeds per day
Worked example
Inputs — Age: 3 months; Feeds per day: 8.
Results — Breast milk per day = 800 mL; Per bottle = 100 mL; Typical range from = 750 mL; Typical range to = 1,035 mL.
Key terms
- Expressed milk
- Breast milk pumped or hand-expressed for bottle feeding.
Frequently asked questions
How much expressed milk should a bottle contain?
Often 90–120 mL (3–4 oz) for babies 1–6 months, depending on feeds per day.
Why does breast milk intake not increase like formula?
Breast milk becomes more energy-dense and babies grow more slowly after the first months.
How do I know my baby is getting enough?
Steady weight gain and 6 or more wet nappies a day after the first week.