Child Height Calculator (Parent-Height Estimate)
Enter both biological parents' heights to see a rough adult-height estimate for a child, the equation behind it and an approximate ±4-inch range.
Uses both biological parents' heights only (AAP method) — not your child's current height, age or weight. Just converting a height? Use cm to feet.
Rough adult-height estimate
Approximate range (±4 in):
AAP parent-height method —
Numbers are rounded for display; the math uses the exact heights you entered.
This is only a rough family-height estimate. Growth patterns and health conditions can change the outcome; talk to your child's pediatrician if you have concerns.
Source: American Academy of Pediatrics, HealthyChildren.org (page updated Sept. 16, 2026; checked Sept. 24, 2026)
Your entered heights stay in this browser tab; copying or downloading is your choice.
How the parent-height estimate works
The American Academy of Pediatrics describes a simple way for parents to estimate a child's adult height from the parents' heights. Use measured heights for both biological parents:
- Boy adjustment: (mother's height + 5 in + father's height) ÷ 2
- Girl adjustment: (father's height − 5 in + mother's height) ÷ 2
For example, a mother who is 5 ft 5 in (65 in) and a father who is 5 ft 10 in (70 in) give ((65 + 5) + 70) ÷ 2 = 70 in, or 5 ft 10 in, with the boy adjustment. With the girl adjustment the same parents give ((70 − 5) + 65) ÷ 2 = 65 in. In centimeters the adjustment is 12.7 cm, because 1 inch is exactly 2.54 cm.
What the ±4-inch range means
The calculator shows the estimate plus or minus 4 inches (about 10 cm). That range is a rule of thumb for how far many children end up from the family estimate. It is not a promise and not a medical confidence interval. Results are rounded to the nearest inch or centimeter for display; the math uses the exact values you entered.
What this calculator does not do
It does not use a child's current height, age, weight or bone age, and it does not check growth charts or percentiles. It cannot account for health conditions, nutrition or treatment. Other methods, such as those that use a child's current measurements, are different calculations and are not offered here. The boy and girl adjustments are the two variables in the published formula, not a statement about a child's gender identity.
When to ask a pediatrician
Growth varies from child to child. If you have concerns about how your child is growing, or this method doesn't fit your family, your pediatrician can look at growth over time on standard growth charts and consider health history.
Privacy
Your entered heights stay in this browser tab; copying or downloading is your choice. Nothing you enter is added to the page address, stored in the browser or sent to ToolNeko. Site analytics record only actions such as calculating or copying, never the heights or the result.
Frequently asked questions
How does the parent-height estimate work?
Add the biological mother's and father's heights in inches, add 5 inches for a boy or subtract 5 inches for a girl, then divide by 2. This is the method the American Academy of Pediatrics describes for parents. The calculator shows the equation with your numbers next to the result.
How exact is ±4 inches?
It is a rough rule of thumb, not a guarantee. Many children end up within about 4 inches of this estimate, but some grow taller or shorter. It is not a medical confidence interval and should not be used to diagnose or plan treatment.
What if I don't know both biological parents' heights?
This method needs both measured heights. It does not guess a missing parent's height. If you only know one, or the boy/girl adjustment doesn't fit your child, ask a pediatrician about an appropriate way to estimate adult height.
Which parents' heights should I use for an adopted or donor-conceived child?
“Mother” and “father” here mean the child's genetic parents, because the formula is about inherited height. If your child was adopted or donor-conceived, use the genetic parents' measured heights, including an egg or sperm donor's, if you know them. If you don't, this method may not apply; your pediatrician can suggest another way to estimate.
Does my child's current height change this result?
No. This method uses only the parents' heights and the formula adjustment. A child's current height, age, weight, bone age and health are not part of it. Methods that use them are different calculations and are not offered here.
When should I talk to a pediatrician?
If you are worried that your child is growing too slowly or too quickly, is much shorter or taller than expected for the family, or has a health condition that may affect growth, ask your pediatrician. They use growth charts and a medical history that a calculator cannot.
Is anything I enter saved or sent?
No. The heights you enter stay in this browser tab and disappear when you reset or close it. They are not put in the page address, saved in the browser or sent in analytics. Copying or downloading a summary is your choice.