Height Calculator

Child Height Predictor

Mother's Height
Father's Height

Result

Predicted Adult Height

Height Converter

Result

Converted Height

How to Use This Height Calculator

Parents ask how tall their kid might end up—and guessing from a growth chart alone gets frustrating when you just want a rough adult-height number to plan for bunk beds or sports tryouts. This calculator covers two jobs: predicting a child's adult height from parent measurements, and converting height between centimeters, inches, and feet-and-inches without mental math.

  • Child Height Predictor — select Child's Gender. Choose Boy or Girl. The formula applies a different offset for each sex.
  • Enter Mother's Height. Type feet in the first field and inches (0–11) in the second for the mother.
  • Enter Father's Height. Fill feet and inches the same way for the father, then press Predict Height. Review Predicted Adult Height in feet, inches, and centimeters.
  • Height Converter — choose Convert From. Pick Centimeters, Inches, or Feet & Inches. Enter a single Value, or separate Feet and Inches fields when Feet & Inches is selected.
  • Select Convert To and press Convert. Pick your output format and read Converted Height in the result table.

For weight on a growth chart, try the Weight Converter or the broader Conversion Calculator. For shoe sizing tied to foot length, see the Shoe Size Conversion Calculator.

Height Calculator Formulas and Practical Applications

The mid-parental height method is a quick genetic estimate pediatricians reference at well visits. It averages parent heights and adjusts for sex—nothing more exotic than arithmetic on total inches.

Parent height to inches

Total Inches = (Feet × 12) + Inches

Mid-parental height (prediction)

Boys: Predicted Height = (Mother + Father + 5) ÷ 2

Girls: Predicted Height = (Mother + Father − 5) ÷ 2

The ±5 inch adjustment reflects average sex differences in final height. Centimeters follow cm = inches × 2.54. Example: mother 5'4" (64 in), father 5'10" (70 in), boy → (64 + 70 + 5) ÷ 2 = 69.5 in ≈ 5'9.5" (177 cm).

Unit conversion

The Height Converter normalizes everything through total inches: centimeters divide by 2.54, feet-and-inches combine as (feet × 12) + inches, then output converts to the target format. That keeps mixed inputs consistent whether you start in metric or imperial.

Standard Units and Conversion Tables

Height appears in different formats depending on country and context—medical records, sports rosters, and clothing charts rarely agree on one label.

  • Feet and inches: Common in the US and UK. One foot = 12 inches.
  • Inches: Useful for precision or when only one number is needed (e.g., 69 in).
  • Centimeters: Standard in most of the world and on WHO growth charts. 1 in = 2.54 cm.
  • Quick reference: 5'0" = 60 in = 152.4 cm; 6'0" = 72 in = 182.9 cm.

Frequently Asked Questions

How accurate is the mid-parental height formula?

It gives a population-average estimate, not a guarantee. Most children finish within about 2 inches (5 cm) of the prediction, but outliers exist—especially with early or late puberty, chronic illness, or exceptional genetic height runs in the family.

Why do boys add 5 inches and girls subtract 5?

The adjustment approximates the average height difference between adult men and women in populations where this formula was developed. It shifts the parental average toward the typical range for the child's sex.

Can I enter parent heights in centimeters?

The height predictor accepts feet and inches for each parent. Use the Height Converter section to translate metric measurements into feet and inches first, then run the prediction.

What units does the Height Converter support?

You can convert from centimeters, inches, or feet and inches to any of those three output formats. All conversions pass through total inches internally for consistency.

Does this predict height at a specific age?

No. The mid-parental method estimates final adult height, not current or next-year height. Pediatric growth charts track progress toward that range over time.

Disclaimer. RapidRatio is informational only—not medical advice. Nutrition, genetics, health conditions, and puberty timing all affect final adult height. Most children land within about 2 inches (5 cm) of the mid-parental prediction, but individual results vary.