How tall is the average 18-year-old boy?
On the CDC stature-for-age chart, the median 18-year-old boy in the reference population measures 176.2 cm (5′ 9.4″). Half are shorter than that and half are taller, which is what "average" means here and is the reason a single number tells you very little on its own.
The usual range is wider than people expect. An 18-year-old boy at the 10th percentile is 166.9 cm (5′ 5.7″) and one at the 90th is 185.3 cm (6′ 0.9″) — 18.4 cm apart, and every child in between is on the chart exactly where they are supposed to be.
CDC stature-for-age percentiles, boys, age 18
| Percentile | Height (cm) | Height (ft/in) | Means |
|---|---|---|---|
| 3th | 162.5 | 5′ 4.0″ | taller than 3% of 18-year-old boys |
| 5th | 164.2 | 5′ 4.7″ | taller than 5% of 18-year-old boys |
| 10th | 166.9 | 5′ 5.7″ | taller than 10% of 18-year-old boys |
| 25th | 171.3 | 5′ 7.5″ | taller than 25% of 18-year-old boys |
| 50th | 176.2 | 5′ 9.4″ | taller than 50% of 18-year-old boys |
| 75th | 181.0 | 5′ 11.3″ | taller than 75% of 18-year-old boys |
| 90th | 185.3 | 6′ 0.9″ | taller than 90% of 18-year-old boys |
| 95th | 187.8 | 6′ 1.9″ | taller than 95% of 18-year-old boys |
| 97th | 189.5 | 6′ 2.6″ | taller than 97% of 18-year-old boys |
Computed from the CDC 2000 stature-for-age LMS parameters (L, M, S) interpolated to 18 years 0 months. These are the same tables a pediatrician's growth chart is printed from, and the same ones the app uses.
Where a percentile is and is not useful
A percentile says where a child stands against other children the same age and sex today. It does not say what they will reach as an adult, and it is not a grade. What matters far more than the number is whether a child holds their own line over time: a boy who has tracked the 25th percentile for three years is growing normally, and one who slid from the 75th to the 25th over the same period is worth a conversation with a pediatrician even though the second number looks unremarkable here.
Parents' heights set roughly the middle of where a child is likely to land. If you want the mid-parental target for your own child, the calculator on the front page does that arithmetic in the browser and nothing is sent anywhere.
Other ages
- 2-year-old boys
- 3-year-old boys
- 4-year-old boys
- 5-year-old boys
- 6-year-old boys
- 7-year-old boys
- 8-year-old boys
- 9-year-old boys
- 10-year-old boys
- 11-year-old boys
- 12-year-old boys
- 13-year-old boys
- 14-year-old boys
- 15-year-old boys
- 16-year-old boys
- 17-year-old boys
Same table for 18-year-old girls →
Putting your own child on the chart
Height Predictor plots a child's measurements on the CDC curve above, keeps the history so the line is visible, and turns it into an adult-height range with the working shown. iPhone only for now.
Open Height Predictor in the App Store
An estimate for curiosity and general wellness, not medical advice. Talk to a pediatrician about any growth concern.