Height Calculator
Gender
in
in
Predicted Height5' 10"
In Centimeters176.5 cm
Range66.0 - 73.0 in
This height calculator predicts a child's adult height from the parents' heights using the mid-parental (target height) method. It averages the two parent heights, adds about 2.5 inches for a boy or subtracts about 2.5 inches for a girl to account for typical sex differences, and reports the estimate in feet, inches, and centimetres. A plus-or-minus range of a few inches reflects the natural variation that genetics, nutrition, and health introduce.
Formula
Boy = (Father + Mother + 5) ÷ 2; Girl = (Father + Mother − 5) ÷ 2 (heights in inches)
- Father
- Father's height in inches
- Mother
- Mother's height in inches
- 5
- Sex adjustment in inches, added for boys and subtracted for girls
How it works
- Choose the child's sex (boy or girl) and enter the father's and mother's heights in inches.
- The calculator averages the parents' heights and adjusts by 5 inches divided between them: it adds the offset for a boy and subtracts it for a girl.
- It shows the predicted adult height in feet/inches and centimetres, with a range of roughly ±3.5 inches around the estimate.
Worked example
Predicting the adult height of a boy whose father is 70 inches and mother is 64 inches tall.
- Sum the parents' heights and add the boy offset: 70 + 64 + 5 = 139 inches.
- Divide by 2: 139 ÷ 2 = 69.5 inches.
- Convert to feet/inches (about 5' 10") and to centimetres: 69.5 × 2.54 = 176.5 cm.
Predicted adult height is about 69.5 inches (5' 10", 176.5 cm), with a likely range of roughly 66 to 73 inches.
Frequently asked questions
- How accurate is a height prediction from parents?
- The mid-parental method gives a reasonable central estimate, but real adult height commonly lands within a few inches either side. Nutrition, overall health, sleep, and individual genetic factors all shift the final result.
- Why add or subtract about 2.5 inches?
- Adult men are on average roughly 5 inches taller than adult women. Splitting that difference adds about 2.5 inches to the parental average for a boy and subtracts about 2.5 inches for a girl.
- What units should I enter?
- Enter both parent heights in inches. The calculator returns the prediction in feet and inches as well as centimetres, so you can read whichever unit you prefer.
- Can it predict height at a specific age?
- No. This tool estimates final adult height only. It does not project height at a particular age or track a growth percentile over time, which require age- and sex-specific growth charts.