Height Chart for 12-Year-6-Month-Old Boys

The CDC median for boys aged 12 years 6 months is 152.7 cm (5 ft 0.1 in), with the 3rd percentile at 138.5 cm and the 97th at 167.4 cm. In the year that starts here the median gains 7.6 cm, 0.2 cm short of the largest 12-month gain after age 6 in the boys' table (7.8 cm, from 12 years 9 months).

CDC standing stature percentiles for boys aged 12 years 6 months. Source: CDC 2000 Growth Charts: stature-for-age, 2-20 years, file statage.csv, row `Sex=1, Agemos=150.5 (completed month 150 band)` (dataset page).
Percentile	Metric	Feet-inches
3rd	138.5 cm	4 ft 6.5 in
5th	140.3 cm	4 ft 7.2 in
10th	143.0 cm	4 ft 8.3 in
25th	147.5 cm	4 ft 10.1 in
50th	152.7 cm	5 ft 0.1 in
75th	157.9 cm	5 ft 2.2 in
90th	162.6 cm	5 ft 4.0 in
95th	165.5 cm	5 ft 5.2 in
97th	167.4 cm	5 ft 5.9 in

Check a height against this row

Accepts 123.4 to 184.8 cm.

How fast the median rises from 12 years 6 months

Of that, 3.7 cm comes in the first 6 months. A year before this age the 12-month gain was 6.3 cm; at 9 years 7 months, the slowest point between ages 4 and 10, it was 4.9 cm.

In the same 12 months the 3rd-percentile value rises 6.6 cm and the 97th-percentile value 7.8 cm. The upper line is still pulling away from the lower one.

Puberty usually starts between ages 9 and 14 in boys, so at 12 years 6 months some children are already growing fast and others have not started. The median row describes the group, not a schedule for one child.

Nearby rows of the CDC stature-for-age table for boys, in centimeters. The last column is the change in the median since the row above.
Age	3rd	50th	97th	Change
10 years 6 months	128.7	141.3	154.4
11 years 6 months	133.1	146.4	160.4	+5.1
12 years	135.7	149.3	163.7	+2.9
12 years 6 months	138.5	152.7	167.4	+3.4
13 years	141.7	156.4	171.3	+3.7
13 years 6 months	145.1	160.3	175.2	+3.9
14 years 6 months	151.8	167.5	181.8	+7.2

Spread at 12 years 6 months

The 3rd-to-97th range is 28.9 cm here, up from 25.7 cm at 10 years 6 months. For boys it is widest at 13 years 9 months, at 30.3 cm. The middle half, 25th to 75th, covers 10.4 cm; a wider range means age alone tells you less about height.

Put another way, the 3rd-percentile height here (138.5 cm) is about the median for boys aged 9 years 11 months (138.4 cm), and the 97th-percentile height (167.4 cm) is about level with the median at 14 years 6 months (167.5 cm).

Girls and boys around 12 years 6 months

From 10 years 9 months to 13 years 2 months the girls' median in the CDC table is higher than the boys'. At 12 years 6 months the girls' median is 154.8 cm and the boys' is 152.7 cm, a difference of 2.1 cm. By 20 the boys' median is 13.5 cm higher.

When to ask a pediatrician

The site's guides list these as reasons to see a pediatrician: no signs of puberty by 14 in boys, puberty that starts before 9, crossing downward through percentile lines, and slow growth together with symptoms such as fatigue or weight loss.

Reference values only, not medical advice. How these tables are built.