How to use the height calculator
- cm to feet and inches and feet and inches to cm: exact conversions in both directions.
- Child's adult height: enter both parents' heights to estimate how tall a child may grow, using the mid-parental height method.
Formulas
1 inch = 2.54 cm exactly · 1 foot = 12 inches = 30.48 cm
Boy: (Father + Mother + 13 cm) ÷ 2 · Girl: (Father + Mother − 13 cm) ÷ 2
The mid-parental method, developed by the paediatrician James Tanner, adds 13 cm (about 5 inches) for a boy or takes it away for a girl, because adult men are on average about 13 cm taller than women. About 95% of children end up within roughly 8.5 cm either side of the estimate.
Worked examples
175 cm ÷ 2.54 = 68.9 inches = 5 ft 8.9 in.
5 ft 9 in = 69 inches × 2.54 = 175.26 cm.
A father of 178 cm and a mother of 165 cm: a boy's estimated adult height is (178 + 165 + 13) ÷ 2 = 178 cm (169.5 to 186.5 cm); a girl's is 165 cm (156.5 to 173.5 cm).
Check a healthy weight for your height with the BMI calculator or the ideal weight calculator.
Frequently asked questions
How accurate is the child height estimate?
It gives a rough target. Most children end up within about 8.5 cm of it, but some fall outside that range.
How tall is 5 ft 10 in in cm?
70 inches × 2.54 = 177.8 cm.
Sources
Formulas checked 29 October 2026. How we test our calculators. This calculator gives general estimates for adults and is not medical advice. Talk to a doctor or dietitian about your own health.