Convert height between feet/inches and centimetres, and predict a child's adult height.
One inch is exactly 2.54 cm (the SI definition since 1959). To go from feet and inches to centimetres, convert to total inches then multiply. The mid-parental height formula adds or subtracts 13 cm for sex difference then averages the parents' heights; the ±10 cm range captures roughly 95% of children from that genetic background.
Feet/inches to centimetres
cm = (feet × 12 + inches) × 2.54
Mid-parental height (boy)
Predicted height (boy) = (Father cm + Mother cm + 13) / 2
Mid-parental height (girl)
Predicted height (girl) = (Father cm + Mother cm − 13) / 2
The mid-parental formula is a population-level estimate with a ±10 cm 95% interval. It does not account for nutrition, health conditions, or early puberty timing. About 1 in 20 children will fall outside the stated range for purely genetic reasons.
Yes — 1 inch = 2.54 cm exactly, so 70 inches × 2.54 = 177.8 cm. The conversion is a defined relationship, not a rounded approximation.
The mid-parental formula predicts the genetic target regardless of current age. For a height prediction based on the child's current measurements and bone age, a paediatrician uses a Bayley-Pinneau or Greulich-Pyle assessment.
Enter 6 in Feet and 1.5 in Inches. The calculator totals 73.5 inches × 2.54 = 186.69 cm.