Height Calculator
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| Predicted Height | |
| Typical Range (±8.5 cm) |
Converting Between Feet/Inches and Centimeters
Height conversion relies on one fixed, internationally agreed constant: 1 inch = 2.54 centimeters exactly (defined by the 1959 international yard and pound agreement). This calculator converts in both directions — enter feet and inches, or enter centimeters directly, and it fills in the rest using that same conversion factor. There's no rounding ambiguity here, unlike some unit conversions: 2.54 cm/inch is exact, so the only imprecision that creeps in is from how many decimal places you choose to report.
Predicting a Child's Adult Height
The mid-parental height method estimates a child's likely adult height from both parents' heights. For a boy: add 13 cm to the mother's height, average it with the father's height. For a girl: subtract 13 cm from the father's height, average it with the mother's height. This is the standard formula used in pediatric growth references, and it exists because it's simple and reasonably accurate on average — but it's a population-level estimate, not a prediction for any one child. Genetics research puts the typical margin of error at roughly ±8.5 cm (about 3.3 inches) around the estimate, reflecting the substantial influence of non-parental factors like childhood nutrition and health. Treat the "typical range" shown here as a rough band, not a guarantee.
Height Alone Doesn't Tell the Whole Story
Height is one input into other health and fitness figures — pair it with the weight calculator to see how it relates to healthy weight ranges, or check shoe size conversion if you're also trying to size footwear across regions.
Frequently Asked Questions
How accurate is the child height prediction?
The mid-parental method is a population-average estimate, not a precise forecast for an individual child. Research on this method puts the typical margin of error at about ±8.5 cm (roughly 3.3 inches), since factors like childhood nutrition, health, and puberty timing also affect final adult height.
Why is 1 inch always exactly 2.54 cm?
This isn't a rounded approximation — it was fixed by international agreement in 1959 (the international yard and pound agreement) so that inches, feet, and the metric system would convert with no ambiguity. Every conversion on this page uses that exact factor.