Height Calculator
Convert height between feet/inches and centimetres, and predict a child's adult height.
About Height Calculator
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
Worked example
With the default values below, Height Calculator returns Centimetres of 177.80. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Modeone of Height Conversion, Child Height Prediction
- Height Conversion
- Input Unitone of Feet & Inches → cm, Centimetres → ft & in
- Feet & Inches → cm
- Feetaccepts 0–9 ft
- 5 ft
- Inchesaccepts 0–11 in
- 10 in
- Centimetresaccepts 0–300 cm
- 177.8 cm
- Child's Sexone of Boy, Girl
- Boy
- Father's Heightaccepts 100–250 cm
- 178 cm
- Mother's Heightaccepts 100–250 cm
- 165 cm
Results
- Centimetres
- 177.80 cm
- Feet
- 5 ft
- Inches
- 10.00 in
- Metres
- 1.7780 m
Step by step
- 1Total inches= 70 in
- 2Convert to centimetres= 177.8 cm
Assumptions and limits
- The result is derived only from the 8 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
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.