Height Calculator
Convert height between feet/inches and centimetres, and predict a child's adult height.
Inputs
Centimetres
177.80cm
Predicted Adult Height
0.0cm
Feet
5ft
Inches
10.00in
Metres
1.7780m
Step by step
Total inches
5 × 12 + 10
= 70 in
Convert to centimetres
70 × 2.54
= 177.8 cm
How it works
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.
Formulas
Feet/inches to centimetres
cm = (feet × 12 + inches) × 2.54
- ft
- Feet component
- in
- Inches component
- h_cm
- Height in centimetres
Mid-parental height (boy)
Predicted height (boy) = (Father cm + Mother cm + 13) / 2
- H
- Predicted adult height (cm)
- H_father
- Father height (cm)
- H_mother
- Mother height (cm)
Mid-parental height (girl)
Predicted height (girl) = (Father cm + Mother cm − 13) / 2
Frequently Asked Questions
How accurate is the child height prediction?
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.
Is 5′ 10″ exactly 177.8 cm?
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.
My child is 8. Can I use this to predict their adult height?
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.
How do I convert 6′ 1.5″ to centimetres?
Enter 6 in Feet and 1.5 in Inches. The calculator totals 73.5 inches × 2.54 = 186.69 cm.