Most babies are on formula until 12 months of age. The American Academy of Pediatrics recommends that infants receive only breast milk or formula as their primary liquid nutrition for the entire first year, with solid foods introduced around 6 months as a complement rather than a replacement.
Why 12 Months Is the Cutoff
The one-year mark isn’t arbitrary. It’s driven by iron. Cow’s milk contains far less iron than formula, and it actually makes it harder for your baby’s body to absorb iron from other foods. Cow’s milk is high in calcium and low in vitamin C, both of which reduce iron absorption. On top of that, the proteins in cow’s milk can cause microscopic bleeding in an infant’s digestive tract, leading to even more iron loss.
Before 12 months, a baby’s digestive system and kidneys also aren’t ready to handle the high protein and mineral load in cow’s milk. During febrile illnesses especially, this can lead to fluid and metabolic imbalances. By a baby’s first birthday, the digestive system has matured enough to process cow’s milk safely, and the child is typically eating enough iron-rich solid foods to compensate for the lower iron content.
How Formula Intake Changes Over the First Year
Formula needs shift significantly as your baby grows. Newborns start with small, frequent feedings that gradually increase in volume. By 6 to 12 months, most babies need formula or solid foods about 5 to 6 times in 24 hours. As solid food intake climbs, formula intake naturally tapers. This is normal and expected. You don’t need to force a set number of ounces. Follow your baby’s hunger cues.
One useful benchmark: babies getting roughly 32 ounces or more of formula daily are covered for vitamin D, since formula is fortified with it. If your baby drops below that amount (common as solids increase), they may need a vitamin D supplement.
Making the Switch to Whole Milk
At 12 months, you can transition from formula to whole cow’s milk. Some babies take to it immediately. Others resist the taste difference. If your baby isn’t a fan, try mixing equal parts whole milk and prepared formula, then gradually shift the ratio toward all milk over a week or two. Children’s Hospital of Philadelphia notes that it’s also fine to offer about an ounce of whole milk in a sippy cup once a day starting around 11 months, just to get your baby used to the flavor before the full switch.
Whole milk should be the choice here, not reduced-fat varieties. Babies under 2 need the fat for brain development. And if your child can’t tolerate dairy, the CDC recommends fortified soy milk as the best plant-based alternative after 12 months. Other options like oat, almond, or coconut milk can work too, but check labels carefully. Look for unsweetened versions fortified with both calcium and vitamin D, since nutrient content varies widely between brands. No plant-based milk should be given before 12 months.
Do Toddler Formulas Extend the Timeline?
Marketing for “stage 3” or toddler formulas suggests your child needs a specialized drink after age one. The AAP disagrees. These products are “generally unnecessary and nutritionally incomplete,” and they offer no benefit over regular cow’s milk for most children older than 12 months. Some are high in added sugar, and they’re consistently more expensive than milk. There’s also no U.S. regulatory oversight ensuring toddler formulas meet any uniform nutritional standards.
Importantly, toddler formulas should never be given to babies under 12 months. They don’t contain the right nutrient profile for infant growth and aren’t a substitute for standard infant formula.
When Formula Might Continue Past 12 Months
Some children do stay on specialized formulas beyond their first birthday. This typically applies to kids with feeding difficulties, those who depend on tube feeding, or those with specific medical conditions that prevent them from getting adequate nutrition from regular food and milk. In these cases, a pediatrician will recommend a particular pediatric formula tailored to the child’s needs. This is a medical decision, not a general recommendation for healthy toddlers.
For the vast majority of babies, the formula chapter closes at 12 months. A varied diet of solid foods plus whole milk (or a fortified alternative) provides everything a healthy toddler needs.