At every doctor visit, your baby’s healthcare provider will take their measurements and plot them on their growth chart.

Because an inch or a pound can make a pretty significant difference in where your baby falls on the charts, your child is measured very carefully. It can be tricky to get reliable and accurate numbers – especially if your baby is very squirmy – but medical staff are experienced at this.

You can also take your baby’s measurements at home, though doing it yourself may not be as accurate as when a doctor, nurse, or medical assistant does it. However, sometimes parents pick up on mistakes made at the doctor’s office or catch growth problems sooner.

Once you have your baby’s measurements, plug them into our growth percentile calculator to find out roughly how your baby compares with other babies the same age.

How to measure head circumference

To measure your baby’s head, a doctor or member of their medical staff places a flexible measuring tape where your baby’s head has the largest circumference – just above the eyebrows and ears, and around the back of the head where it slopes up prominently from the neck.

Why does the size of your baby’s head matter? Because the size of their skull reflects the growth of their brain.

So if a baby’s brain isn’t growing and developing normally, their head circumference may not be increasing as it should. On the other hand, if the skull grows too quickly, it could be a sign of a problem like hydrocephalus (the buildup of fluid in the brain). Both conditions are unlikely, but important to rule out.

By the way, babies’ heads are disproportionately large compared to adults’ heads, so don’t worry if your baby’s head looks big to you. Consider your own proportions, too: If you or your partner has a large or small head, your baby might, too.

To measure your baby’s head circumference at home:

  • Wrap a flexible, non-stretchable measuring tape around their head at the widest part – just above the eyebrows and ears, and around the back where the head slopes up prominently from the neck.
  • The goal is to measure your baby’s head at the spot where it has the largest circumference.
  • Take the measurement three times and choose the largest measurement to the nearest 0.1 cm.

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How to measure your baby’s weight

At the doctor’s office, you undress your baby completely – that’s right, no diaper – and a staff member places them on a scale. Weight is measured in pounds to the closest ounce or in kilograms to the nearest tenth of a kilo.

To measure your baby’s weight at home:

  • If you don’t have a baby scale, any accurate scale will do. Undress your baby (no diaper), hold your baby, and get on the scale together. Write down that number.
  • Then put your baby down in a safe place and get on the scale alone. Subtract that number from your combined weight to get your baby’s approximate weight.

How to measure your baby’s length (height)

While your child is lying down, a doctor, nurse, or medical assistant measures them from the top of their head to the bottom of their heel. Some doctors use a special device with a headboard and a movable footboard for more accurate results.

To measure your baby’s length at home:

  • Lay your baby down and stretch a measuring tape from the top of their head to the bottom of their heel. It’s easiest if you have someone help because you’ll need to gently stretch your baby’s leg straight to do this.
  • Record the length to the nearest 0.1 cm.
  • Your number probably won’t be exactly the same as the doctor’s, but you’ll get a ballpark figure.

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