My baby is thinner than other babies in the family. Should I worry?
Probably not. Babies are compared with the WHO standard, not with cousins. If your baby is feeding well, active, and gaining steadily along their curve, they're growing well.
How much should my baby weigh each month?
Reviewed by Dr Abhas Gupta, MBBS, MD, DNB (Paediatrics), PDCC (Paediatric Rheumatology) • About Dr Abhas Gupta (Bio) • Last reviewed: 28 September 2026
There's no single "correct" weight for a baby. Healthy babies come in a wide range of sizes. What your pediatrician really looks at is whether your baby keeps growing along their own curve, month after month.
That said, it helps to know what the normal range looks like. The chart below shows it.
The short answer
- Most babies are back to their birth weight by 10 to 14 days.
- Most babies double their birth weight by about 4 to 5 months.
- Most babies triple their birth weight by about 12 months.
- A single weighing tells you very little. Two or three weighings over a few months tell you a lot.
Baby weight chart by month (in kg)
These are the WHO Child Growth Standards, which the Indian Academy of Pediatrics recommends for all Indian children under 5.
The middle column is the 50th percentile, the typical weight. The normal range runs from the 3rd to the 97th percentile. A baby anywhere in this range can be perfectly healthy.
Boys
| Age | Low end of normal (3rd) | Middle (50th) | High end of normal (97th) |
|---|---|---|---|
| Birth | 2.5 kg | 3.3 kg | 4.3 kg |
| 1 month | 3.4 kg | 4.5 kg | 5.7 kg |
| 2 months | 4.4 kg | 5.6 kg | 7.0 kg |
| 3 months | 5.1 kg | 6.4 kg | 7.9 kg |
| 4 months | 5.6 kg | 7.0 kg | 8.6 kg |
| 5 months | 6.1 kg | 7.5 kg | 9.2 kg |
| 6 months | 6.4 kg | 7.9 kg | 9.7 kg |
| 7 months | 6.7 kg | 8.3 kg | 10.2 kg |
| 8 months | 7.0 kg | 8.6 kg | 10.5 kg |
| 9 months | 7.2 kg | 8.9 kg | 10.9 kg |
| 10 months | 7.5 kg | 9.2 kg | 11.2 kg |
| 11 months | 7.7 kg | 9.4 kg | 11.5 kg |
| 12 months | 7.8 kg | 9.6 kg | 11.8 kg |
Girls
| Age | Low end of normal (3rd) | Middle (50th) | High end of normal (97th) |
|---|---|---|---|
| Birth | 2.4 kg | 3.2 kg | 4.2 kg |
| 1 month | 3.2 kg | 4.2 kg | 5.4 kg |
| 2 months | 4.0 kg | 5.1 kg | 6.5 kg |
| 3 months | 4.6 kg | 5.8 kg | 7.4 kg |
| 4 months | 5.1 kg | 6.4 kg | 8.1 kg |
| 5 months | 5.5 kg | 6.9 kg | 8.7 kg |
| 6 months | 5.8 kg | 7.3 kg | 9.2 kg |
| 7 months | 6.1 kg | 7.6 kg | 9.6 kg |
| 8 months | 6.3 kg | 7.9 kg | 10.0 kg |
| 9 months | 6.6 kg | 8.2 kg | 10.4 kg |
| 10 months | 6.8 kg | 8.5 kg | 10.7 kg |
| 11 months | 7.0 kg | 8.7 kg | 11.0 kg |
| 12 months | 7.1 kg | 8.9 kg | 11.3 kg |
Want your baby's exact percentile? Enter their weight in our free growth calculator.
How much weight should my baby gain each week?
Weight gain is fastest in the first few months and slows down after that. As a rough guide:
- 0 to 3 months: about 150 to 250 g a week
- 3 to 6 months: about 100 to 150 g a week
- 6 to 12 months: about 50 to 80 g a week
Don't worry if one week is lower than this. Babies grow in spurts. Look at the trend over a month, not a single week.
The first week: some weight loss is normal
Almost all newborns lose some weight in the first few days. This is mostly extra fluid, and it's expected. A loss of up to about 7 to 10% of birth weight is usually fine, and most babies are back to their birth weight by 10 to 14 days.
If your baby has lost more than this, or hasn't regained birth weight by 2 weeks, get your baby checked. It usually means feeding needs a little help, and it's easy to fix early.
My baby is on a low percentile. Is that bad?
Not by itself. A baby who has always been on the 10th percentile and stays there is usually just a smaller baby, often with smaller parents. That's healthy.
What matters more is change. If your baby was on the 50th percentile and has dropped to the 10th, that's worth a conversation with your pediatrician, even if the 10th percentile is still "in range".
A few things that change the picture
Babies born early. If your baby was born before 37 weeks, use their corrected age (age from their due date, not their birth date) when you compare with the chart, until about 2 years of age.
Babies born small. Low birth weight babies often grow faster than average for a while to catch up. Your pediatrician will watch their curve rather than compare them with the middle column.
Illness. A bout of loose motions, fever or a cold can cause a small dip. Most babies catch up within a couple of weeks once they're well and eating again.
How to weigh your baby accurately
- Use the same scale each time, ideally the one at your clinic.
- Weigh without clothes or nappy, or with the same light clothing each time.
- Try to weigh at a similar time of day, not straight after a big feed.
- Home bathroom scales are not accurate enough for babies. A difference of 200 g can just be the scale.
When should I talk to a pediatrician?
Talk to your pediatrician if:
- Your baby hasn't regained birth weight by 2 weeks
- Your baby is below the 3rd or above the 97th percentile
- Your baby's weight has dropped across two or more percentile lines on the chart
- Your baby is losing weight, or not gaining over a month
- Your baby has fewer than 6 wet nappies a day after the first week, or seems to be feeding poorly
- You're worried for any reason. You know your baby best.
Questions parents often ask
Should I give formula or extra feeds to make my baby gain faster?
Not without talking to your pediatrician first. A healthy baby growing along their own curve doesn't need to be pushed to a higher one. Overfeeding can bring its own problems.
Is a chubby baby a healthier baby?
No. A baby on the 97th percentile isn't healthier than one on the 25th. Both can be perfectly healthy. What matters is steady growth.
Why do boys and girls have different charts?
Boys are, on average, slightly heavier and longer than girls from birth. Using the right chart makes the comparison fair.
Are WHO charts right for Indian babies?
Yes. The WHO standards were built from healthy, breastfed babies in six countries, including India, and describe how babies grow when their needs are met. The Indian Academy of Pediatrics recommends them for children under 5.
Sources & clinical references
- World Health Organization. WHO Child Growth Standards: Weight-for-age (2006).
- Indian Academy of Pediatrics Growth Charts Committee. Revised IAP growth charts for height, weight and body mass index for 5- to 18-year-old Indian children. Indian Pediatrics, 2015.