Average Baby Weights in the First Year

Dana LaneBaby Care, Online Childbirth Classes for Natural Birth

Average Baby Weights in the First Year

Making sure your baby is growing and healthy is a parent’s top priority.  It can kind of get confusing though with growth charts and percentiles galore.  In this post we will look at the average baby weights month to month and explain what it all means.

Average Baby Weights:  Well Checks, Growth Charts & Percentiles,  Oh My!

Average Baby Weights - Percentiles like head circumference

Right from birth, your baby starts to collect stats sch as weight, length, and head circumference.

When a baby is born, they are instantly assigned stats like Apgar scores, weight, and length.  As the weeks and months go on, more stats are added with each “well check” at the pediatrician.  It can start to feel like a math word problem.  “If my darling baby is 7 lbs at birth and breastfeeds 12 times a day, what should his percentile be by three months?”

Average baby weight - newborn weight

Even though it can get a little overwhelming, data such as average baby weights are important. And despite popular belief, the point isn’t to compare your baby to other babies!  Doctors use the data to chart your baby’s development at each appointment.  This helps them to get an accurate picture of your baby’s growth over time.  What doctors care about most are the consistent trends in the way your individual baby gains weight, height, or head circumference.  A discrepancy in the trend of your baby’s growth rate can alert your doctor to possible health concerns (1).

Average Baby Weights:  Looking at the Charts

The best charts to help you view the details of average baby weights in the United States are provided by the Center for Disease Control (CDC) and the National Center for Health Statistics.  Here is the growth chart for male babies  (2) and the growth chart for female babies (3).

Let’s break it down to make it a little simpler to read, shall we?  We’ve converted kg into lbs and are featuring the approximate, average weight found in the middle-of-the-road 50th percentile of baby weight.

BOY 50th% Average Baby Weights

1st Month: 9 lbs 13 oz

2nd Month: 12 lbs 4 oz

3rd Month: 14 lbs 0.9 oz

4th Month: 15 lbs 6 oz

5th Month: 16 lbs 8 oz

6th Month: 17 lbs 7 oz

7th Month: 18 lbs 4 oz

8th Month: 18 lbs 15 oz

9th Month: 19 lbs 9 oz

10th Month: 20 lbs 3 oz

11th Month: 20 lbs 12 oz

12th Month: 21 lbs 4 oz

GIRL 50th% Average Baby Weights

1st Month: 9 lbs 3 oz

2nd Month: 11 lbs 4 oz

3rd Month: 12 lbs 14 oz

4th Month: 14 lbs 2 oz

5th Month: 15 lbs 3 oz

6th Month: 16 lbs 1 oz

7th Month: 16 lbs 13 oz

8th Month: 17 lbs 8 oz

9th Month: 18 lbs 2 oz

10th Month: 18 lbs 11 oz

11th Month: 19 lbs 3 oz

12th Month: 19 lbs 11 oz

Although these are the “average” weights, it doesn’t mean a baby with a weight lower or higher than these numbers is not healthy.  In fact, normal weights can vary greatly from child to child.  For instance, a healthy 6-month old in the 10th percentile can be about 15 lbs 2 oz while another equally health 6-month old in the 95th percentile may weigh 18 lbs 10 oz.

Genetics, culture, environment and parental feeding choices greatly influence babies weights. So, it’s important to not get too hung up on numbers by themselves (1).  Remember, your doctor is trying to see a broad picture of the way your individual baby is developing, not to compare your child with others.

Average Baby Weights:  Developmental Milestones

Since we are having so much fun with graphs and data (ha ha), another fantastic resource is the “Milestone Checklist” from the CDC https://www.cdc.gov/ncbddd/actearly/pdf/checklists/all_checklists.pdf  (3) Each page includes age appropriate milestones and ideas to help encourage your child’s healthy growth and development along the way, from age 2 months up to 5 years.

Average Baby Weights: Milestone Checklists

Milestone Checklists

The Milestone Checklist also gives you some warning signs that can be addressed with your pediatrician if you feel that your baby’s growth or development isn’t where it should be.  Never be afraid to bring up any concerns, thoughts and questions.  As the mom or dad, you’re the expert when it comes to your child.  Your unique relationship enables you to provide key pieces of information that can help the doctor create an accurate picture of your baby’s health and growth.

Average baby weight - developmental milestones

Watching your child learn and develop is one of the joys of being a parent.  While charts, data points and graphs can help gauge baby’s progress, try not to get hung up in the details.  Baby’s first year is full of exciting changes and milestones.  So be sure to take pictures, write down special memories, and enjoy this precious time in your baby’s life!

Kopa Birth’s online childbirth classes allow you to prepare for a natural childbirth from the comfort of your own home, 24/7. Enroll today in our free online childbirth class to learn more about preparing for a natural hospital birth.


(1) Swanson, W.S (2014 ) Mama Doc Medicine: Finding Calm and Confidence in Parenting, Child Health, and Work-Life Balance

(2) Data Table for Boys Length-for-age and Weight-for-age Charts, National Center for Health Statistics Retrieved from https://www.cdc.gov/growthcharts/who/boys_length_weight.htm

(3) Data Table for Girls Length-for-age and Weight-for-age Charts, National Center for Health Statistics Retrieved from https://www.cdc.gov/growthcharts/who/girls_length_weight.htm

(4) CDC Milestone Checklist retrieved from https://www.cdc.gov/ncbddd/actearly/pdf/checklists/all_checklists.pdf