- Average weight at 11 months: girls 19 lb 4 oz (8.7 kg), boys 20 lb 12 oz (9.4 kg), the WHO median or 50th percentile.
- The usual range (3rd to 97th percentile) is 15 lb 6 oz to 24 lb 5 oz for girls and 16 lb 14 oz to 25 lb 7 oz for boys.
- The curve matters more than the number. A baby who keeps following roughly the same line is growing well, wherever that line is.
- Born early? Use the corrected age until 2 years.
What percentile is my 11-month-old?
Type your baby's weight and we'll open the growth percentile calculator set to 11 months, with your baby's percentile, curve and a plain-words verdict. Add the real birth date there for an exact result.
11-month-old girls: weight, length and head percentiles (WHO)
| 3rd | 15th | 50th (average) | 85th | 97th | |
|---|---|---|---|---|---|
| Weight | 15 lb 6 oz 7.0 kg | 16 lb 15 oz 7.7 kg | 19 lb 4 oz 8.7 kg | 21 lb 14 oz 9.9 kg | 24 lb 5 oz 11.0 kg |
| Length | 26¾ in 68.0 cm | 27½ in 70.2 cm | 28¾ in 72.8 cm | 29¾ in 75.4 cm | 30½ in 77.5 cm |
| Head | 16½ in 42.0 cm | 17 in 43.2 cm | 17½ in 44.6 cm | 18 in 46.0 cm | 18½ in 47.1 cm |
11-month-old boys: weight, length and head percentiles (WHO)
| 3rd | 15th | 50th (average) | 85th | 97th | |
|---|---|---|---|---|---|
| Weight | 16 lb 14 oz 7.7 kg | 18 lb 8 oz 8.4 kg | 20 lb 12 oz 9.4 kg | 23 lb 4 oz 10.5 kg | 25 lb 7 oz 11.5 kg |
| Length | 27½ in 70.2 cm | 28½ in 72.1 cm | 29¼ in 74.5 cm | 30¼ in 77.0 cm | 31 in 78.9 cm |
| Head | 17 in 43.4 cm | 17½ in 44.4 cm | 18 in 45.8 cm | 18½ in 47.1 cm | 19 in 48.2 cm |
WHO Child Growth Standards 2006, at exactly 11 months (day 335; one month = 30.4375 days). Length is measured lying down until 2 years. The bold column is the median; the 15th to 85th percentiles hold the middle 70% of babies.
What's typical at this age
Just before the first birthday a typical baby weighs about 2.7 to 2.8 times their birth weight. Girls are now about 9¼ in (24 cm) longer than at birth, and boys about 9¾ in (25 cm). Appetite can swing a lot from day to day now, which is normal; growth is judged over months, not meals.
- Weight gain: about 2¼ oz (65 g) a week at this stage (WHO median).
- Since birth: 2.7 times the birth weight for girls and 2.8 for boys, and about 9¼ in (24 cm) to 9¾ in (25 cm) longer.
- Next checkup: the 12-month checkup (AAP Bright Futures schedule).
- Sleep: usually 2 naps, with 3 to 4 hours awake in between. The nap planner turns that into a day.
How to read the table
A percentile compares your baby with 100 healthy babies of the same age and sex. The 15th percentile for weight means your baby is heavier than 15 of them and lighter than the other 85. It is not a grade: the 50th is the middle of the crowd, not the goal. Look at weight, length and head together; a baby on the 20th for weight and the 20th for length is simply a smaller baby in proportion.
Crossing two or more of the main lines over time, especially downward, is what pediatricians like to look into. The growth calculator tracks that for you: add each checkup and it draws the curve and tells you how many bands it has moved.
Born early?
For a premature baby, compare with babies of the same corrected age, counted from the due date, until about 2 years. A baby born 8 weeks early is compared at 11 months with the 9-month table. The corrected age calculator works it out, and the growth calculator uses it when you add the due date.
Questions
My 11-month-old is on the 90th percentile. Is that a problem?
No. One in ten healthy babies is at or above it, and big babies of tall parents often stay big. The usual range runs up to the 97th percentile, 24 lb 5 oz (11.0 kg) for girls and 25 lb 7 oz (11.5 kg) for boys at 11 months. What your pediatrician watches is the weight-for-length and whether the curve keeps its shape, not the height of the line.
How much should an 11-month-old gain per week?
Around 2¼ oz (65 g) a week is typical at this stage on the WHO standards. Week-to-week numbers jump with feeds, diapers and the scale, so compare over a month. Add two measurements to the growth calculator and it shows your baby's own weekly gain next to the typical one.
How big is the difference between boys and girls at 11 months?
On the WHO medians a boy is about 1 lb 8 oz (690 g) heavier and ¾ in (1.8 cm) longer than a girl. That is why the charts are separate: a girl on the 30th percentile and a boy on the 30th weigh different amounts.
Sources
- World Health Organization, WHO Child Growth Standards (2006): the weight-for-age, length-for-age and head-circumference-for-age tables. The numbers on this page come from the LMS tables in the WHO anthro package.
- CDC, Recommended growth charts (WHO charts from birth to 2, CDC charts from 2).
- American Academy of Pediatrics, Bright Futures periodicity schedule (checkup ages and screenings).
- Paruthi S. et al., Recommended amount of sleep for pediatric populations, American Academy of Sleep Medicine consensus, endorsed by the AAP (J Clin Sleep Med, 2016).
Spotted a mistake or an outdated figure? Write to [email protected].