Mid-parental target height with the likely range pediatricians use
Updated October 2026
Use the biological parents’ measured heights, without shoes, in inches or centimeters. Measured heights are better than remembered ones, so measure both parents against a wall the same way you would measure the child. The method only works with both biological parents’ heights; for an adopted child, or when one parent’s height is unknown, the child’s own growth chart is the better guide.
The result gives the target adult height, the likely range (8.5 cm, about 3.3 inches, either side), and where the target sits on the CDC growth chart at age 20, for men or for women.
| Child | Target height | Likely range |
|---|---|---|
| Boy | (father + mother + 13 cm) ÷ 2 | ±8.5 cm (about ±3.3 in) |
| Girl | (father + mother − 13 cm) ÷ 2 | ±8.5 cm (about ±3.3 in) |
The 13 cm (about 5 inches) is the average difference between adult men and women. With a 70-inch father (177.8 cm) and a 64-inch mother (162.56 cm): (177.8 + 162.56 + 13) ÷ 2 = 176.68 cm for a son, which is 69.6 inches. The likely range is 168.2 to 185.2 cm (66.2 to 72.9 inches). For a daughter, subtract 13 instead of adding it: (177.8 + 162.56 − 13) ÷ 2 = 163.68 cm, or 64.4 inches.
| Father / mother | Son: target (range) | Son’s adult percentile | Daughter: target (range) | Daughter’s adult percentile |
|---|---|---|---|---|
| 66 in / 61 in | 66.1 in (62.7–69.4) | 10th | 60.9 in (57.6–64.3) | 9th |
| 68 in / 63 in | 68.1 in (64.7–71.4) | 29th | 62.9 in (59.6–66.3) | 30th |
| 70 in / 64 in | 69.6 in (66.2–72.9) | 49th | 64.4 in (61.1–67.8) | 52nd |
| 72 in / 66 in | 71.6 in (68.2–74.9) | 76th | 66.4 in (63.1–69.8) | 80th |
| 75 in / 69 in | 74.6 in (71.2–77.9) | 96th | 69.4 in (66.1–72.8) | 98th |
The percentile columns place the target on the CDC adult reference at age 20. A child’s actual height can fall anywhere in the range shown.
Tanner and colleagues published growth standards that allow for mid-parental height in 1970, and the mid-parental target is still the routine first check. The Royal Children’s Hospital Melbourne guideline (reviewed July 2025) gives the ±8.5 cm normal range for final height and lists four reasons to refer a short child: height below the 3rd percentile, height out of keeping with mid-parental height, dropping height percentiles, or other features that suggest an underlying condition. In a UK study of 419 children aged 8 to 9, 90% were within about two percentile spaces of their mid-parental height (Wright and Cheetham, 1999).
Very tall or very short parents. Children of unusually tall parents tend to end up less tall than the formula says, and children of short parents less short, so the same study found the simple formula misleading for families at the extremes. Remembered heights instead of measured ones shift the target. Early or late puberty. An early developer may look tall at 11 and finish near the target; a late developer may look short at 13 and catch up. Reading the target as a promise. It is the middle of a range, not a forecast for one child. Using it for a teen who has stopped growing adds nothing: once growth plates close, measured height is the adult height.
This calculator gives a family-based estimate, not an assessment of a child’s growth. Pediatricians use the child’s own measurements over time: the growth rate, how the child’s percentile compares with the mid-parental target, and sometimes a hand X-ray for bone age. Ask the pediatrician if your child is below the 3rd percentile for height, is dropping across percentile lines, is far below the family’s expected range, or starts puberty much earlier or later than peers. Do not start supplements or treatments meant to increase height based on a prediction.