Height calculator: how tall will I be?

It gives a rough estimate, best read as a range. The American Academy of Pediatrics puts the margin of error at about 10 cm (4 inches) either way, which is the range this calculator shows. The formula only knows the parents’ heights, not the child’s own height, growth speed or puberty.

There is an old rule of thumb: double a boy’s height at age 2, or a girl’s at 18 months, since girls develop faster. The American Academy of Pediatrics notes that no research shows how accurate it is, so it is a rough guess at best.

Use the mid-parental height formula: add the mother’s and the father’s height, add 13 cm (5 inches) for a boy or take 13 cm away for a girl, and divide by two. The 13 cm is the average difference in height between adult men and women. For a 180 cm father and a 165 cm mother, that gives about 179 cm for a son and 166 cm for a daughter, each give or take about 10 cm.

No. Height can only be estimated while a child is still growing. Once the growth plates close, by the end of puberty, it can be measured but no longer predicted.

Any time something about a child’s growth or puberty worries you. A doctor can measure properly, plot it on a growth chart and look for a reason if there is one. Some common reasons people ask:

• growth seems to slow down or stall
• height seems far off from the rest of the family
• puberty seems to start much earlier or later than usual
• worry about height is affecting mood, eating or sleep

No. The calculation runs in your browser. The heights you enter aren’t sent anywhere or stored, and they’re gone when you close the page.