Average height for a 3-year-old boy
At exactly 3 years old, the median boy in the US is 3'1½" (95.0 cm) tall, according to the CDC growth charts. Half of 3-year-old boys are between 3'0½" and 3'2½", and about 9 in 10 fall between 2'11" and 3'4".
Height percentiles for 3-year-old boys
CDC 2000 stature-for-age chart, at 3 years 0 months.
| Percentile | Height | cm | in |
|---|---|---|---|
| 3rd | 2'10½" | 88.1 | 34.7 |
| 5th | 2'11" | 88.9 | 35.0 |
| 10th | 2'11½" | 90.2 | 35.5 |
| 25th | 3'0½" | 92.4 | 36.4 |
| 50th (median) | 3'1½" | 95.0 | 37.4 |
| 75th | 3'2½" | 97.6 | 38.4 |
| 90th | 3'3½" | 100.1 | 39.4 |
| 95th | 3'4" | 101.6 | 40.0 |
| 97th | 3'4½" | 102.6 | 40.4 |
What’s typical at 3 for boys
Between 3 and 4, the median boy grows about 3 in (7.3 cm) — from 3'1½" to 3'4".
A median 3-year-old boy has reached about 54% of the CDC's median adult height for men (5'9½"), so roughly 32 in (81.9 cm) of growth is still typical from here.
This is the steady stretch of childhood: growth runs at a fairly even pace and most boys track along the same percentile line year after year. Puberty, and the growth spurt that comes with it, is still years away — boys typically start between 9 and 14.
How to read a percentile
A percentile compares a child with others of the same age and sex on the CDC 2000 growth charts — the same L, M and S values a pediatrician’s chart is drawn from, and where every number on this page comes from. The 50th percentile is the median: half of boys that age are shorter and half are taller. The 5th and 95th bracket the middle 90%.
Pediatricians care less about the number than the line. A child who stays near the same percentile year after year is growing normally, whatever that percentile is — a steady 15th is healthier than a 60th that has just dropped from the 90th. Crossing two of the major lines, or sitting below the 3rd, is the usual cue to have a pediatrician take a look. None of this is medical advice.
How tall will a 3-year-old boy be as an adult?
Height at 3 is one input. The calculator combines it with both parents’ heights and puberty timing to give the range adult height will most likely land in — free, no account.
Try the height calculatorThe MaxHeight app shows the number inside that range and sharpens it as you log — free to download on the App Store.
Source: CDC 2000 growth charts, stature-for-age LMS parameters (statage.csv). Adult figures: NHANES 2015–2018. MaxHeight is not affiliated with or endorsed by the CDC.