During the first few months of life, babies gain about 1 ounce per day, which works out to roughly 1.5 to 2 pounds per month. That rate slows as babies get older, dropping to about 1 pound per month by the second half of the first year. These are averages, and individual babies can vary quite a bit while still being perfectly healthy.
Weight Loss in the First Week
Before babies start gaining, they actually lose weight. It’s normal for newborns to lose up to 7% of their birth weight in the first few days as they adjust to feeding and lose excess fluid. Most babies regain their birth weight by about day 10. So if your baby weighed 7.5 pounds at birth, a dip to around 7 pounds in those early days is expected.
Birth to 3 Months: The Fastest Growth
This is the period of most rapid weight gain. At roughly 1 ounce per day, babies typically put on 1.5 to 2 pounds each month during the first three months. You may notice your baby looking noticeably bigger from one week to the next, and outgrowing newborn clothes quickly. Growth spurts commonly happen around 2 to 3 weeks and again around 6 weeks, during which babies feed more frequently and may seem fussier than usual. These spurts usually last only a few days.
3 to 6 Months: Steady but Slowing
Weight gain starts to taper slightly, averaging about 1 to 1.25 pounds per month. By 6 months, most babies have doubled their birth weight. That’s a useful milestone to keep in mind: a baby born at 7.5 pounds would typically weigh around 15 pounds by the half-year mark. Another growth spurt commonly occurs around the 3-month and 6-month marks, bringing a temporary increase in appetite and fussiness.
6 to 12 Months: A Gradual Slowdown
From 6 months through the first birthday, weight gain slows further to roughly 0.5 to 1 pound per month. Babies are now more active, rolling, crawling, and eventually pulling to stand, which burns more calories. By 12 months, most babies have tripled their birth weight. That same 7.5-pound newborn would weigh approximately 22 to 23 pounds at their first birthday.
After the First Birthday
Growth slows considerably in the second year. Toddlers between 12 and 24 months gain about 5 pounds over the entire year, averaging less than half a pound per month. This is completely normal and reflects the natural shift from rapid infant growth to a slower, steadier pace. Many parents notice their toddler’s appetite becoming less predictable during this time, which matches the reduced need for calories.
Breastfed vs. Formula-Fed Babies
Breastfed and formula-fed babies follow slightly different weight gain curves. For the first three months, their patterns are similar. After that, formula-fed infants typically gain weight more quickly. Breastfed babies tend to put on weight more slowly through the rest of the first year. This difference persists even after solid foods are introduced. Both patterns are healthy. Length growth is similar regardless of feeding method.
This difference matters when your baby’s weight is plotted on a growth chart. The CDC recommends using World Health Organization (WHO) growth charts for children under 2 years. The WHO charts are based on healthy, predominantly breastfed infants and represent how children grow under optimal conditions, rather than simply describing how a particular population happened to grow. If your pediatrician uses the older CDC reference charts for a breastfed baby, the baby may appear to be falling behind when they’re actually growing normally.
What Matters More Than Monthly Numbers
A single weight check doesn’t tell you much. What pediatricians look for is a consistent pattern over time, specifically whether your baby is following their own growth curve on a standardized chart. Some babies track along the 25th percentile, others along the 75th, and both are perfectly fine. The concern arises when a baby steadily drops away from the curve they’ve been following across multiple visits.
Signs that weight gain may be inadequate include a baby who is consistently not gaining over several weeks, seems unusually lethargic, has fewer wet diapers than expected, or is crossing downward through percentile lines on their growth chart. A single slow week, especially during an illness, is rarely a concern on its own.
Growth spurts can also make the pattern look uneven. Your baby might plateau for a week or two and then gain rapidly. This is why tracking weight over months gives a much clearer picture than weighing your baby at home day to day.
Quick Reference by Age
- 0 to 3 months: about 1.5 to 2 pounds per month
- 3 to 6 months: about 1 to 1.25 pounds per month
- 6 to 12 months: about 0.5 to 1 pound per month
- 12 to 24 months: about 5 pounds total over the year
- Double birth weight: around 6 months
- Triple birth weight: around 12 months