How your baby gains weight

Weighing your baby helps you know if they are growing and healthy. You should check your baby’s weight regularly. It helps make sure they are getting the food they need.

It’s a good idea to have your baby’s weight checked regularly.

Babies are usually weighed:

  • once a month up to 6 months
  • every 2 months from 6 to 12 months
  • every 3 months after their first birthday

What affects your baby’s birth weight

Your baby’s birth weight will depend on how close they were born to their due date. Babies born after their due date are often larger, and those born earlier are often smaller.

Your baby’s birth weight is strongly influenced by the mother’s health and diet before and after birth.

It can also be affected by:

  • parents’ height and weight
  • the baby’s health when born

Girls, first babies and children of multiple births are often smaller. Boys, single babies and babies born second, third or more in the family are often larger.

If your baby is born underweight or overweight, they might get more attention to look out for possible problems.

General guidelines for growth

All babies grow differently. But there are guidelines for healthy weight gain.

A useful guide is that most healthy, full-term newborn babies double their birth weight by four months and triple it by their first birthday. A boy’s weight will triple in about 13 months. A baby girl’s weight will triple in about 15 months. However, all babies grow at their own pace.

The first months

All babies lose weight after they are born.

Healthy babies normally lose anything up to a 10th of their birth weight in the first week. This is because breastfed babies receive only small amounts of colostrum for the first few days. Then mothers begin producing the breastmilk that will help them grow.

Healthy babies usually get back to their birth weight in 2 to 3 weeks.

Read more about breastfeeding and feeding with formula.

Sudden weight change

Your baby’s weight gain might slow down because:

  • your baby starts to sleep more and feed less often
  • you or your baby become ill
  • you’re feeling stressed
  • you’re pregnant or taking contraceptive medicines

If your baby seems happy and healthy, you might choose to wait and watch. Adding a couple of breastfeeds a day might ‘top up’ if supply is a bit low.

If you’re worried, see your doctor, nurse or midwife or call Pregnancy, Birth and Baby on 1800 882 436.

Your baby’s growth records

Your baby’s weight and other measurements will be recorded in your baby’s health record, when you visit a clinic, doctor or hospital.

This record helps doctors, nurses and others check your baby’s health, growth and development against what would be expected.

Your baby’s weight and length will be plotted on a graph that also shows normal weights and lengths for babies at different ages. This shows how your baby is growing between check-ups.

Read about your baby’s developmental milestones.