If an infant is not breastfed, infant formula provides the energy and nutrients needed for healthy growth and development. Commercial infant formulas sold in the U.S. are designed to closely match the nutrient composition of breast milk and are regulated to meet strict safety and nutritional standards.
Healthcare professionals such as your baby’s pediatrician can help you choose the type of formula that’s most appropriate for your baby’s specific needs. Different formulas are available depending on your baby’s tolerance, digestive needs, and any medical recommendations.
It’s important never to make homemade infant formula using cow’s milk, plant milks, or other substitutes. Homemade formulas do not provide the correct balance of nutrients and can place a baby’s kidneys under stress or negatively affect growth and development.
How much formula does a baby need?
Because every infant is unique, there’s no exact amount that all babies require. Many infants are fed on demand, guided by hunger cues, especially in the first weeks and months.
General guidance suggests that newborns taking only formula may feed about 8–12 times per 24 hours in the early weeks, with amounts per feed gradually increasing as the baby grows.
The packaging on formula containers includes recommended amounts, but these are just guidelines. If your baby doesn’t finish a bottle, it’s okay — you shouldn’t force them to finish it. Your pediatrician or nurse monitors your baby’s weight and length over time; as long as your baby follows a healthy growth curve, there’s usually no need to worry about inadequate intake.
Combining breastfeeding and formula
In some situations, parents choose to combine breastfeeding with formula feeding. For many families this works well, but in some cases introducing a bottle early may reduce stimulation of breast milk production, or the baby may prefer the faster flow from a bottle. If this is a concern, some parents choose to offer formula in a cup first, or wait until breastfeeding is well established before introducing formula. Discuss your feeding plan with a pediatrician or lactation specialist.
How to prepare infant formula
Because infants are vulnerable to infections and imbalances in nutrients, hygiene and careful preparation are essential:
- Wash your hands thoroughly before preparing formula.
- Use clean bottles and nipples; they should be washed and rinsed after each use.
- Don’t use hot tap water directly from the faucet — instead start with cold water from a safe source.
- Follow the manufacturer’s instructions on the formula container exactly: add water first, then the correct amount of formula powder. Too much or too little water can harm your baby.
- Only mix one bottle at a time and use it promptly. Prepared formula should be used within 2 hours at room temperature or within 24 hours if refrigerated.
Async feeding practices such as microwave heating are not recommended — microwaves can cause uneven heating and increase the risk of burns. Instead, warm bottles in a bowl of warm water and always test the temperature before feeding.
Why you shouldn’t dilute infant formula with extra water
Infant formula is carefully designed to provide the exact balance of nutrients, calories, and electrolytes that a baby needs. When extra water is added, this balance is disrupted.
Over-diluting formula can lead to several serious health risks, especially in young infants:
Water intoxication (hyponatremia): Too much water can dilute sodium levels in the baby’s blood. This can cause symptoms such as irritability, sleepiness, low body temperature, seizures, and in severe cases can be life-threatening.
Inadequate nutrition: Diluted formula provides fewer calories and nutrients per feed, which can interfere with weight gain and healthy growth.
Strain on immature kidneys: Babies’ kidneys are not fully developed and cannot handle excess water efficiently, increasing the risk of electrolyte imbalance.
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