This ideal baby weight chart shows the typical weight of baby boys and girls each month from birth to 2 years, using the WHO Child Growth Standards that Indian paediatricians follow. A baby boy is typically about 6.4 kg at 3 months and 7.9 kg at 6 months; a baby girl about 5.8 kg and 7.3 kg.
These are medians, the middle of the healthy range. Babies who are smaller or larger can be just as healthy if they keep growing along their own line on the chart.
Quick numbers
Birth (median)
boys 3.3 kg, girls 3.2 kgWeight doubles
by about 4 to 5 monthsWeight triples
by about 12 monthsGain, first 3 months
about 150 to 200 g a weekSource
WHO Child Growth Standards
Ideal baby weight chart, month by month
| Age | Baby boy (kg) | Baby girl (kg) |
|---|---|---|
| Birth | 3.3 | 3.2 |
| 1 month | 4.5 | 4.2 |
| 2 months | 5.6 | 5.1 |
| 3 months | 6.4 | 5.8 |
| 4 months | 7.0 | 6.4 |
| 5 months | 7.5 | 6.9 |
| 6 months | 7.9 | 7.3 |
| 7 months | 8.3 | 7.6 |
| 8 months | 8.6 | 7.9 |
| 9 months | 8.9 | 8.2 |
| 10 months | 9.2 | 8.5 |
| 11 months | 9.4 | 8.7 |
| 12 months | 9.6 | 8.9 |
| 15 months | 10.3 | 9.6 |
| 18 months | 10.9 | 10.2 |
| 24 months | 12.2 | 11.5 |
Use the line for your baby's sex. Premature babies are judged by corrected age, counting from their due date, until about 2 years.
Normal weight range for babies
| Age | Boys (kg) | Girls (kg) |
|---|---|---|
| 3 months | 5.0 to 8.0 | 4.5 to 7.5 |
| 6 months | 6.4 to 9.8 | 5.7 to 9.3 |
| 9 months | 7.1 to 11.0 | 6.5 to 10.5 |
| 12 months | 7.7 to 12.0 | 7.0 to 11.5 |
Most healthy babies fall inside these ranges. Being near the edge is not a problem by itself; crossing lines on the chart over a few months is what doctors look for.
Ideal weight of 1 to 3 month babies
In the first week, babies often lose up to 7 to 10 percent of birth weight and regain it by 10 to 14 days. After that, gain is fast: about 150 to 200 g a week. An ideal weight of a 1 month baby is roughly 4.2 to 4.5 kg, of a 2 month baby 5.1 to 5.6 kg, and of 3 months baby around 5.8 to 6.4 kg, girls at the lower figure.
Ideal weight of 4 to 6 month babies
Gain slows to about 100 to 150 g a week. At 4 months, a baby girl is typically around 6.4 kg and a boy 7.0 kg. The ideal weight of a 5 month baby is near 6.9 to 7.5 kg, and of a 6 month baby about 7.3 to 7.9 kg. Around 6 months, solid food starts alongside breast milk.
7 to 12 months and beyond
From 7 months, gain is about 50 to 100 g a week. By the first birthday, most babies weigh close to three times their birth weight: about 8.9 kg for girls and 9.6 kg for boys. After 1 year, growth slows to about 2 to 2.5 kg a year. For older children see weight by age.
How to weigh a baby at home
- Weigh yourself, then weigh yourself holding the baby, and subtract.
- Use the same scale each time, with the baby in a dry nappy only.
- Pick one time slot, ideally before a feed, and keep to it.
- Home scales can be off by 100 to 200 g; clinic weights are more reliable.
When to see the paediatrician
See a doctor quickly if your baby has fewer than six wet nappies a day after the first week, is not back to birth weight by 2 weeks, seems very sleepy, feeds poorly, or loses weight at any age.
Regular check-ups at vaccination visits include weight and length. Ask to see the growth chart. For birth weight questions, see the newborn weight page; the child BMI page explains why BMI is not used before age 2.
Baby boy vs baby girl
Boys are on average 200 to 600 g heavier than girls through the first year. Use the right chart for the sex of the baby; a healthy girl compared with a boy's chart can look underweight when she is not.
Frequently asked questions
What is the ideal weight of a 6 month baby?
About 7.9 kg for boys and 7.3 kg for girls by the WHO median. Most healthy 6 month olds are between 5.7 and 9.8 kg.
What is the ideal weight of a 3 months baby?
Around 6.4 kg for boys and 5.8 kg for girls.
What is the ideal weight for a 4 months baby girl?
About 6.4 kg, with a normal range of about 5 to 8 kg.
How much weight should a baby gain each month?
About 600 to 800 g a month in the first three months, 400 to 600 g from 4 to 6 months, and less after that.
Is my baby underweight?
Not if they follow their own line on the growth chart and feed and wet nappies well. Ask your paediatrician to plot the weight.
When does a baby double the birth weight?
Usually by 4 to 5 months, and triple it by about 12 months.
Sources
- WHO Child Growth Standards
- Indian Academy of Pediatrics