After the birth of a baby, one of the parent’s biggest concerns is to ensure the baby’s health. A normal weight and height indicate that the baby is growing and healthy. To make sure that your baby is healthy, it is required that you go for regular pediatric checkups as only the doctor can indicate whether a particular baby is healthy or not.

How Much Should a 3 Month Old Weigh?

  • Weight of a 3 month old: Weight of a 3 months old baby boy should be 6.4 kg or 14.1 lbs. The weight of a 3 month old female baby should be 5.8 kg or 12.8 lbs. These weights lie at the 50th percentile on the weight charts used by most doctors to chart growth of infants.

  • Height of a 3 month old: Height of a 3 month old female baby should be around 60 cm or 23.6 inches whereas of a male baby should be around 61.5 cm or 24.2 inches. These heights lie at the 50th percentile on the height charts used by doctors of infants 0 to 6 months old.

Development of Your 3-Month-Old Baby

After knowing the answer to the question how much should a 3 month old weigh, let’s discuss other developments that need to be noticed of a 3 month old baby.

Motor Skills

The innate reflexes, including the startle reflex that your baby displayed during the first couple of months, should be gone by now. Your baby’s strength of neck is improving and while you hold them upright you will notice very little or even no wobbling of head. A 3 month old baby should also have enough strength in their upper body to support their chest and head with their arms while they are lying on their stomach and enough strength in their lower body to stretch out their legs and do kicking movement.

Your baby should also show some early signs of eye-hand coordination. Your baby’s hands can come together, open and shut, grab a rattle or toy briefly, swipe at colorful dangling toys and go straight into the mouth.


The nervous system of your 3 month old baby is maturing and more milk or formula can be accommodated by his stomach. Due to these changes he can sleep for six to seven hours at a given time. If your baby cries during the night, wait for about thirty seconds before heading into nursery. Many a times, babies go back to sleep themselves after crying for a few seconds. If you go into the nursery at his first sound of crying, he will not learn falling back asleep on his own.

If he cries continuously and you have to go into the nursery during the night, do the essentials. If possible, changing and feeding must be carried out in the dark and then the baby should be transferred back to his crib. Eventually, he will realize that night time is meant for sleeping only.

The daytime schedule of your baby should also be in a routine by this time. Majority of the three month old babies take a few naps of around 1 1/2 to 2 hours every day.

The Senses

“How much should a 3 month old weigh?” is not the only question that you should concern, you should also be aware about the development of the senses of your 3 month old baby. The vision and hearing of your baby are improving. At this age, babies turn their heads, love listening to all kinds of music and smile at the sound of their parents’ voices.

Your baby will still prefer looking at brightly colored toys. This is because it is easier for them to see sharp contrasts. 3-month old babies are fascinated by faces. If you look at him, you will find him staring back into your eyes. Your baby will also stare intently at his own reflection in a mirror of the crib.


A 3 month old baby is now becoming a unique human being. This is the stage, referred to as hatching, when your baby will begin to come out of his shell and start to react and relate to the world around him. Smiling for pleasure, referred to as social smiles and interacting with people are a part of this process of hatching.

Crying is no more your baby’s primary method of communication. In fact, a 3 month old baby should not cry for more than an hour every day. If your baby’s crying period exceeds this, you should visit a pediatrician, because reflux or another medical problem may be the reason behind this excessive crying.

What You Should Know

Every baby is unique. Don’t be panicked if your 3 month old baby misses a milestone, especially if his was a premature birth. However, do visit your pediatrician if your 3 month old baby hasn’t done the following:

  • He hasn’t smiled

  • He hasn’t given response to noises

  • He hasn’t reached for objects

  • He hasn’t followed objects or people with his eyes

Average Weight and Height for Babies and Toddlers

How much should a 3 month old weigh? Now you have got the answer and also known a lot about the growth of a three month old baby. In order to help you to understand the growth of your baby at different periods, following are the charts that you can refer to before visit for a regular checkup.

Average Height and Weight for Newborn and Infants





18.9 to 19.8 inches

19.1 to 20.1 inches


6.5 to 7.8 pounds

6.7 to 8.1 pounds

3 Months


23.0 to 24.1 inches

23.6 to 24.7 inches


11.8 to 14.0 pounds

13.0 to 15.2 pounds

6 Months


25.3 to 26.5 inches

26.1 to 27.2 inches


14.8 to 17.5 pounds

16.2 to 18.8 pounds

9 Months


27.0 to 28.3 inches

27.7 to 28.9 inches


16.7 to 19.7 pounds

18.2 to 21.1 pounds

Average Height and Weight for Toddlers



    12 Months


28.5 to 29.8 inches

29.2 to 30.5 inches


18.2 to 21.4 pounds

19.8 to 22.9 pounds

   15 Months


29.9 to 31.2 inches

30.5 to 31.8 inches


19.5 to 23.0 pounds

21.1 to 24.5 pounds

   18 Months


31.0 to 32.5 inches

31.7 to 33.1 inches


20.8 to 24.5 pounds

22.4 to 26.0 pounds

   21 Months


32.1 to 33.8 inches

32.7 to 34.3 inches


22.0 to 26.0 pounds

23.6 to 27.5 pounds


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