Breast Milk Intake Calculator
Estimate how much expressed breast milk a baby needs per day and per feeding from body weight, using the 150 mL/kg guideline.
How it works
Daily milk (mL) = weight (kg) × 150 · Per feeding = daily ÷ feedings/day · weight (kg) = lb × 0.4536
For the first several months, a common guideline is that a baby takes about 150 mL of breast milk per kilogram of body weight over 24 hours — equivalent to roughly 2.5 oz per pound. Breastfed babies at the breast regulate intake themselves, so this figure is most useful when you are feeding expressed milk by bottle and need a starting amount. Distribute it across the typical 8–12 feeds a young baby has each day and adjust to the baby’s cues.
Worked example
A 10 lb baby weighs 4.54 kg, so 4.54 × 150 ≈ 680 mL (about 23 oz) per day. Across 8 feeds that is roughly 85 mL (≈2.9 oz) per feeding.
Frequently asked questions
How is this different from the formula calculator?
The numbers are close, but breast milk is typically dosed as 150 mL/kg/day while formula uses the 2.5 oz/lb rule with a 32 oz cap. Both are starting estimates; a directly breastfeeding baby needs no measured amount at all.
How many times a day should a young baby feed?
Newborns often feed 8–12 times in 24 hours. As they grow, feeds become larger and less frequent. This calculator lets you set the number of feeds so the per-feed amount matches your baby’s rhythm.
Should intake keep rising as the baby grows?
Daily volume rises with weight for the first months, then levels off and eventually falls once solid foods begin around 6 months. Let weight gain and diaper counts, not a fixed target, guide you.
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This is a general educational estimate, not medical advice. Every child grows, feeds and responds to medicine differently — for anything about your child’s health, growth, nutrition or medication, follow the guidance of your pediatrician.