Medically the evaluation by Carissa Stephens, R.N., CCRN, CPN — written by MaryAnn De Pietro, CRT — updated on September 6, 2021

Weight is one indicator of good nutrition and physical development. That can therefore be valuable to know about babies’ mean weight month by month.

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First, the is precious noting that mean weight is not “normal” weight. Similar to adults, babies come in every shapes and sizes. If a baby’s weight is in a lower percentile, this does not necessarily signal a difficulty with their growth or physical development. V this in mind, utilizing a load chart can help a person generally track your baby’s growth.

The Centers for disease Control and Prevention (CDC) recommend using the people Health organization (WHO) weight chart because that babies up to 2 years of age.

This article describes the median weight the a infant month through month indigenous birth. It also explores what can influence a baby’s weight.

Average infant weights

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According to the WHO, the typical birth load of a full-term masculine baby is 7 pounds (lb) 6 ounces (oz), or 3.3 kilograms (kg). The typical birth weight of a full-term female is 7 lb 2 oz, or 3.2 kg.

The typical weight that a infant born at 37–40 weeks varieties from 5 lb 8 oz to 8 lb 13 oz. This is 2.5 to 4 kg. In ~ delivery, experts consider a low birth weight to be much less than 5 lb 8 oz, or 2.5 kg.

It is typical for babies to lose roughly 10% of their weight shortly after birth. This decrease is mostly due to fluid loss and usually nothing to issue about. Most babies gain back this weight within 1 week.

Baby weight chart by age

Weight charts can assist a person tell what percentile your baby’s weight drops into. For example, if their weight is in the 60th percentile, it method that 40% the babies the the same age and also sex weigh more, and also 60% of this babies sweet less.

This does no necessarily typical that any type of baby weighs too much or too little. It deserve to simply show where a baby’s weight drops on a spectrum.

The chart below shows baby weights in the 50th percentile. This is the mean weight. Male babies have tendency to sweet a little much more than woman babies, for this reason the chart is split by sex.

Baby ageFemale 50th percentile weightMale 50th percentile weight
Birth7 lb 2 oz (3.2 kg)7 lb 6 oz (3.3 kg)
1 month9 lb 4 oz (4.2 kg)9 lb 14 oz (4.5 kg)
2 months11 lb 5 oz (5.1 kg)12 lb 4 oz (5.6 kg)
3 months12 lb 14 oz (5.8 kg)14 lb 1 oz (6.4 kg)
4 months14 lb 3 oz (6.4 kg)15 lb 7 oz (7.0 kg)
5 months15 lb 3 oz (6.9 kg)16 lb 9 oz (7.5 kg)
6 months16 lb 1 oz (7.3 kg)17 lb 8 oz (7.9 kg)
7 months16 lb 14 oz (7.6 kg)18 lb 5 oz (8.3 kg)
8 months17 lb 8 oz (7.9 kg)18 lb 15 oz (8.6 kg)
9 months18 lb 2 oz (8.2 kg)19 lb 10 oz (8.9 kg)
10 months18 lb 11 oz (8.5 kg)20 lb 3 oz (9.2 kg)
11 months19 lb 4 oz (8.7 kg)20 lb 12 oz (9.4 kg)
12 months19 lb 12 oz (8.9 kg)21 lb 4 oz (9.6 kg)

What to expect

Babies grow and gain weight the fastest within the very first 6 months of life. Back this can vary, babies have tendency to gain about 4–7 oz, or 113–200 grams (g), per week in the very first 4–6 months.

Weight gain then slowly slightly, v an average get of about 3–5 oz (about 85–140 g) every week when the baby is 6–18 months. On average, babies triple their birth load by their very first birthday.

Growth patterns carry out not follow a clean schedule, however. Some babies obtain weight steadily and also stay in the same percentile, or close to it, for several months. Others obtain weight rapidly, signalling a development spurt, which can occur at any time. This might move a baby right into a brand-new weight percentile.

What affects baby weight?

It is important not to focus on weight together the just indicator of physics development. Other dimensions of this advance include the baby’s length and head circumference.

Considering all 3 measurements provides doctors an idea about how the baby is growing, compared with other babies that the exact same age and also sex.

Meanwhile, it is additionally important come keep various other developmental landmarks in mind. Assorted checklists of milestones by period are available, including one from, i beg your pardon is endorsed by institutions such as the American Academy the Pediatrics and also the national Association the Pediatric Nurse Practitioners.

For everyone looking for much more information around what impacts the weight of a baby, several determinants can it is in involved, including:


Male newborns often tend to it is in bigger than female newborns, and they commonly gain load a small faster throughout infancy.


Weight gain and growth rates can likewise depend on even if it is the baby consumes breast milk or formula.

The American Academy the Pediatrics notes that breastfed babies get weight and grow much faster than formula-fed babies throughout the first 6 months.

However, that price can transition during the next 6 months. Breastfed babies may acquire weight and also grow an ext slowly 보다 formula-fed babies as soon as they space aged 6 months to 1 year.

Medical conditions

Underlying health concerns can reason a infant to get weight more slowly. Because that example, babies through congenital heart irregularities may obtain weight in ~ a slower price than babies there is no this condition.

Health issues that affect nutrient absorb or digestion, such as celiac disease, may additionally lead to sluggish weight gain.


Babies born prematurely may grow and gain weight much more slowly throughout their an initial year than babies born at complete term.

However, countless babies born prematurely gain weight rapidly and also “catch up” by around their an initial birthday.

The average birth weight for full-term male babies is 7 lb 6 oz, or 3.3 kg. Because that female babies born full-term, the median birth load is 7 lb 2 oz, or 3.2 kg. Infant weight charts can aid a health care team track a baby’s physical advance by comparing the baby’s weight with the weights of others of the same age and sex.

Still, a medical professional usually look at for steady growth, fairly than a target percentile, once assessing a baby’s physics development. And also even if a baby’s weight is in a lower percentile, they will certainly not have to be a tiny adult — just as longer babies carry out not necessarily become tall adults.

Knowing about average weights by month can aid people gauge their babies’ physics development, yet doctors additionally look because that other necessary indicators, such together length and head circumference.

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Healthcare professionals likewise take into account even if it is a baby is normally hitting other turning points on time. And also by acquisition a detailed medical history, they can rule out any kind of medical problems or nutritional considerations that might be staying clear of a infant from obtaining weight appropriately.