- Average weight at 5 months: girls 15 lb 3 oz (6.9 kg), boys 16 lb 9 oz (7.5 kg), the WHO median or 50th percentile.
- The usual range (3rd to 97th percentile) is 12 lb 1 oz to 19 lb 3 oz for girls and 13 lb 6 oz to 20 lb 5 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 5-month-old?
Type your baby's weight and we'll open the growth percentile calculator set to 5 months, with your baby's percentile, curve and a plain-words verdict. Add the real birth date there for an exact result.
5-month-old girls: weight, length and head percentiles (WHO)
| 3rd | 15th | 50th (average) | 85th | 97th | |
|---|---|---|---|---|---|
| Weight | 12 lb 1 oz 5.5 kg | 13 lb 6 oz 6.1 kg | 15 lb 3 oz 6.9 kg | 17 lb 4 oz 7.8 kg | 19 lb 3 oz 8.7 kg |
| Length | 23½ in 59.8 cm | 24¼ in 61.7 cm | 25¼ in 64.0 cm | 26 in 66.3 cm | 26¾ in 68.2 cm |
| Head | 15¼ in 39.0 cm | 15¾ in 40.1 cm | 16¼ in 41.5 cm | 16¾ in 42.8 cm | 17¼ in 43.9 cm |
5-month-old boys: weight, length and head percentiles (WHO)
| 3rd | 15th | 50th (average) | 85th | 97th | |
|---|---|---|---|---|---|
| Weight | 13 lb 6 oz 6.1 kg | 14 lb 12 oz 6.7 kg | 16 lb 9 oz 7.5 kg | 18 lb 9 oz 8.4 kg | 20 lb 5 oz 9.2 kg |
| Length | 24½ in 61.9 cm | 25 in 63.7 cm | 26 in 65.9 cm | 26¾ in 68.1 cm | 27½ in 69.9 cm |
| Head | 15¾ in 40.3 cm | 16¼ in 41.3 cm | 16¾ in 42.6 cm | 17¼ in 43.8 cm | 17¾ in 44.8 cm |
WHO Child Growth Standards 2006, at exactly 5 months (day 152; 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
Five months is a quiet stretch between checkups, and a common time for parents to notice the percentile slipping a little. That is usually catch-down growth, not a feeding problem: weekly gain halves compared with the first three months. If you want to check the amounts, the feeding calculator gives the typical range by weight and age.
- Weight gain: about 4 oz (110 to 120 g) a week at this stage (WHO median).
- Since birth: 2.1 times the birth weight for girls and 2.2 for boys, and about 5¾ in (15 cm) to 6¼ in (16 cm) longer.
- Next checkup: the 6-month checkup (AAP Bright Futures schedule).
- Sleep: usually 3–4 naps, with 1½ to 2½ 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 5 months with the 3-month table. The corrected age calculator works it out, and the growth calculator uses it when you add the due date.
Questions
My 5-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, 19 lb 3 oz (8.7 kg) for girls and 20 lb 5 oz (9.2 kg) for boys at 5 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 a 5-month-old gain per week?
Around 4 oz (110 to 120 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.
Which growth chart does my pediatrician use?
In the US, the CDC and the American Academy of Pediatrics recommend the WHO growth charts from birth to 2 years, the same ones as on this page, and the CDC charts from age 2. So the percentile you see here should match your pediatrician's for a baby under 2, give or take the rounding of a home scale.
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].