What Is the Average Baby Weight by Month?

Baby weight is a major indicator of physical development and good nutrition. Hence it is necessary to know about babies’ average weight each month up to 2 years.

Just like adults, babies come in various sizes and shapes. So if your baby’s weight is lower than normal, it can indicate an issue with their physical development and growth.

Keeping this in mind and using a weight chart for babies can help track your baby’s growth.

This blog explains the average baby weight and what factors can affect it. 

Average Baby Weight

Average baby weights

According to the World Health Organization (WHO), the average baby weight for a male baby should be about 3.3 kgs, and for a female baby, it should be 3.2 kg. 

However, at 37–40 weeks of birth, the average weight should range from 2.5 to 4 kg.

At delivery, a weight less than 2.5 kgs is considered a low birth weight. Babies lose about 10% of their body weight soon after birth.

But there is no need to worry about this, as this decrease is because of the loss of body fluid that accumulates when the baby is in the womb. As a result, most babies get back to normal weight in 1 week.

To know about average baby weight or baby care tips, you can consult your neonatologist’s doctor. We have the best Neonatologist in Pune having vast experience in this field.

Weight percentiles and the Baby weight chart 

The average baby Weight charts can tell you what percentile your baby’s weight can fall into. For instance, if your baby’s weight is at the 60th percentile, 40% of babies of a similar sex and age group and sex weigh more, and about 60% of babies weigh less.

This doesn’t show that your baby weighs too little or too much. It simply means that your baby’s weight falls on a particular spectrum.

The chart below shows baby weights in the 50th percentile, the average weight. male babies weigh slightly more than female babies.

Baby age

 Female baby in 50th percentile weight

Male baby in 50th percentile weight
Birth3.2 kg3.3 kg
1 month4.2 kg4.5 kg
2 months5.1 kg5.6 kg
3 months5.8 kg6.4 kg
4 months  6.4 kg  7.0 kg
5 months6.9 kg7.5 kg
6 months7.3 kg7.9 kg
7 months7.6 kg8.3 kg
8 months7.9 kg8.6 kg
9 months8.2 kg8.9 kg
10 months8.5 kg  9.2 kg
11 months8.7 kg9.4 kg
12 months8.9 kg9.6 kg

Doctors track your baby’s weight percentile; a low percentile may be a sign of failure to thrive and lead to malnourishment. In contrast, a high percentile shows a growth spurt.

What to expect from weight gain in babies?

Babies gain weight the fastest within the first 6 months of life. After that, some babies put on weight steadily while others gain rapidly, showing a growth spurt.

Healthy newborn babies lose some birth weight following delivery, as the extra fluid they are born with is eliminated quickly. As a result, rapid weight gain is common shortly afterward.

You can expect your baby to be fussier before or during a growth spurt. In this period, your baby may sleep and eat more. After the growth spurt, you may notice that your baby moves to the next size up in clothing. After some time, your baby’s weight gain may slow down.

What affects baby weight?

Most times, even premature babies gain weight quickly and catch up to their normal weight percentile by their first birthday. Here are a few factors that affect baby weight:

Average Baby Weight

1. Genetics. Your size during your birth time can also determine your baby’s size.

2. Length of pregnancy. Babies born before or at their due date could be small or normal-sized. In comparison, babies born past the due date are larger than usual.

3. Nutrition during pregnancy. A healthy pregnancy diet can help your baby’s growth in your womb and after birth.

4. Lifestyle habits during pregnancy. Harmful habits such as drinking alcohol, smoking, or recreational drugs impact your baby’s birth weight.

5. Your baby’s sex. At birth, male babies have more weight than female babies.

6. Health conditions of mother in pregnancy. Having underlying conditions such as high blood pressure, diabetes, heart disease, and obesity during pregnancy can indirectly affect your baby’s weight.

7. Number of babies in the womb. Having twins, triplets, or more can affect an individual baby’s weight, based on how much space they get for themselves inside the womb.

8. Your baby’s health. Medical issues like infection or congenital disabilities have a major impact on your baby’s weight.

Why is baby weight important?

Your baby’s weight is an important measure that your doctor uses to determine your baby’s development or detect any underlying concerns.

When your babies get little food or the wrong type of food, they become malnourished. Experts suggest that underfeeding (days versus weeks or months) can cause permanent damage to your baby’s body. However, these are serious yet short-term consequences. 

Timing is the key factor; underfeeding in the first days after birth may cause malnutrition or even medical conditions like jaundice and low blood sugar (hypoglycemia). 

What should you do if you’re concerned about your baby’s health?

Talk to your doctor if you’re concerned that your baby is overweight or underweight. Your doctor will show your baby’s growth rate and give you the nutritional therapy plan required for your baby. This plan can help determine the feedings for your baby per day. Health concerns that you may experience with your baby are:

  • If your baby is not gaining enough weight and your breast milk is low, your doctor might recommend formula milk, which is one type of cow’s milk made suitable for babies.
  • If your baby has trouble suckling, your doctor will guide you with some find positions to hold your baby right and make breastfeeding easy for your baby.
  • Another way to determine whether your baby is taking insufficient nutrition is to check for bowel movements and wet diapers they produce regularly.
  • The number of bowel movements declines as your baby gets older. So your baby may not be getting enough nutrition if the stools or urine output is low. 

If you find these unusual signs in your baby, consult with your doctor immediately.


Your baby’s weight helps you and your doctor track your baby’s growth and development. However, gaining weight slowly or quickly can have future health consequences if not addressed on time.

Remember, your baby’s weight at birth is not an indicator of their health as adults. Premature babies or babies with low birth weight can quickly gain back normal weight and catch up with their peers. Overweight babies can easily reach a healthy weight range.

If you have any queries about average baby weight by month, consult with our experts.

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