Baby Formula Calculator (how much formula per feed and per day)

Understanding the baby formula calculator — concept and principle

This calculator estimates how much infant formula a baby aged 0–6 months typically takes per day and per feed, using the American Academy of Pediatrics guide of about 2½ fl oz per pound of body weight per day, and compares it with the UK guide of about 150 mL per kg. Parents and carers of formula-fed babies use it.

Weight-based daily amount — with the default inputs: 130 mL per feed.

How it is calculated

AAP daily amount = weight (kg) × 75 mL ÷ 0.4536 (about 165 mL per kg)
Per feed = daily amount ÷ feeds per day
fl oz = mL ÷ 29.5735
UK guide = weight × 150 mL
AAP daily ceiling: about 32 fl oz (960 mL)

The principle

A baby's milk needs grow roughly with body weight in the first months. The AAP says a formula-fed baby takes on average about 2½ fl oz (75 mL) a day for each pound of body weight, and usually no more than about 32 fl oz a day. UK NHS guidance for babies under 6 months uses about 150 mL per kg. Both are averages: appetites vary from day to day, during growth spurts and with illness.

Worked example

Defaults: 5.5 kg, 2 months, 7 feeds a day.

AAP daily amount = 5.5 × 75 ÷ 0.4536 = 909 mL = 30.8 fl oz.
Per feed = 909 ÷ 7 = 130 mL = 4.4 fl oz.
UK guide = 5.5 × 150 = 825 mL a day.
Daily ceiling (AAP) = 960 mL.

How to read the result

Use the figures as a rough starting point. Babies show hunger by rooting, sucking on hands or fussing, and fullness by turning away, slowing or falling asleep. Follow those cues rather than making a baby finish every bottle. Steady weight gain, enough wet nappies and contentment between feeds are good signs. In the first week babies take much less, about 30–60 mL per feed.

Common mistakes

Using the formula for newborns in the first days.
Making up formula with the wrong amount of water.
Encouraging a baby to finish every bottle.
Applying the guide after 6 months, when solid food replaces some milk.

Keep in mind: Not medical advice. Always follow the formula's preparation instructions, and ask your health visitor or doctor if you are worried about feeding or weight.

Frequently asked questions

How much formula should a 2-month-old drink?

Roughly 150–165 mL per kg per day; for 5.5 kg about 825–910 mL.

What is the maximum per day?

The AAP suggests usually no more than about 32 fl oz (960 mL).

How many feeds a day?

Newborns often 8–12; at 1–2 months about 7–8; at 6 months about 4–5.

Sources: American Academy of Pediatrics, HealthyChildren.org, "Amount and Schedule of Baby Formula Feedings" · NHS Healthier Together, "Infant formula – essential prescribing information"

Checked 9 Nov 2026. American Academy of Pediatrics, HealthyChildren.org, “Amount and Schedule of Baby Formula Feedings” (2½ oz per lb per day, at most about 32 oz in 24 hours); NHS Healthier Together, “Infant formula – essential prescribing information” (150 mL/kg/day under 6 months).

Your numbers