Baby Milk Calculator NHS
This independent UK baby milk calculator gives a rough daily formula milk range for babies from about 1 week to 6 months using body weight. It is not a feeding prescription and should not be used to limit responsive feeding.
Formula milk estimate
How much formula milk does a baby need?
UK NHS-family guidance commonly uses a rough guide of 150–200 ml of formula per kg of body weight per day after the first week until around 6 months. Babies vary, so this range is a starting point rather than a target that must be finished.
How to use the calculator
- Select your baby’s age group.
- Enter current weight in kilograms.
- Select Calculate.
- For babies from 1 week to under 6 months, the tool shows the rough daily formula range.
Formula and methodology
For the 1-week-to-under-6-month age group: lower estimate = weight × 150 ml and upper estimate = weight × 200 ml. This calculation is for formula feeding guidance. Breastfed babies should generally feed responsively rather than being assigned a calculated daily breast-milk volume.
Worked example
For a 6 kg baby, the rough formula guide is 6 × 150 = 900 ml to 6 × 200 = 1,200 ml per day. This does not mean the baby must drink that exact amount.
Responsive bottle feeding
NHS advice recommends feeding when your baby shows hunger cues and stopping when they show they have had enough. Never force a baby to finish a bottle. Weight gain and wet and dirty nappies help indicate whether a baby is getting enough milk.
Safe formula preparation
Follow the manufacturer’s instructions exactly. NHS advice says to make feeds one at a time as needed, use the correct water-to-powder ratio, and discard formula left in the bottle after a feed. Do not add extra powder or extra water.
From around 6 months
As solid foods are introduced, babies usually take less formula. NHS guidance for 7–9 months says formula-fed babies may need around 600 ml a day, but this is only a guide. Breast milk or first infant formula remains an important main drink through the first year.
Authoritative sources
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FAQs
How much formula does my baby need per day?
After the first week and until around 6 months, 150–200 ml per kg per day is a rough guide used in UK NHS-family guidance. Individual needs vary.
Should I make my baby finish every bottle?
No. NHS advice says not to force a baby to finish a feed. Follow hunger and fullness cues.
Can I use this calculation for expressed breast milk?
Not as a fixed target. Breast-milk intake and feeding patterns vary, so discuss expressed-milk needs with a midwife or health visitor if you need individual guidance.
Does the same formula apply after 6 months?
No. Milk intake changes as solid foods are introduced, so a simple weight-based formula is less appropriate.
Medical disclaimer: This calculator provides a rough formula-feeding guide only. It is not a prescription and does not replace advice from your midwife, health visitor, GP, paediatrician or dietitian. Seek professional advice if you are concerned about feeding, growth, hydration or illness.