Health July 13, 2026 · 8 Min Read

Baby Height Calculator – Guide & Formulas

Track your infant's length / height percentile and estimate their future adult height using the mid-parental method.

Like weight, an infant's length or height is a primary indicator of healthy skeletal development. This Baby Height Calculator evaluates your baby's current length percentile against WHO growth curves, and uses the validated Mid-Parental Height formula to predict your baby's eventual height as a fully grown adult.

Key Takeaway

Use the free Baby Height Calculator to track your infant's length / height percentile and estimate their future adult height using the mid-parental method. Get instant results with step-by-step explanations.

How to Use the Baby Height Calculator

  1. Select your baby's biological sex and current age (0 to 24 months).
  2. Enter your baby's current length in inches or centimeters.
  3. Provide the mother's and father's adult heights to generate an adult height forecast.
  4. Check current percentiles and estimated final height.

The Formula

Boys Projected Adult Height = (Father's Height + Mother's Height + 5 inches) / 2 | Girls Projected Adult Height = (Father's Height + Mother's Height - 5 inches) / 2

Variable Definitions

  • Father's Ht: The biological father's adult stature
  • Mother's Ht: The biological mother's adult stature

Predicting Final Adult Height

A baby boy has a biological father who is 72 inches tall (6'0") and a mother who is 64 inches tall (5'4").

  1. Step 1: Set Father Height = 72 in, Mother Height = 64 in.
  2. Step 2: Add parent heights: 72 + 64 = 136 in.
  3. Step 3: Add 5 inches for a boy: 136 + 5 = 141 in.
  4. Step 4: Divide by 2: 141 / 2 = 70.5 inches (5'10.5").
  5. Step 5: The boy's estimated adult height is 5 feet 10.5 inches, with a typical standard error range of +/- 2 inches.

Frequently Asked Questions

How accurate is the mid-parental adult height predictor?

While genetically grounded, the mid-parental formula is an estimate. It accounts for approximately 70-80% of height variation, while environmental factors like nutrition, sleep, and medical health during childhood account for the rest.

What is the difference between infant "length" and "height"?

For babies under 2 years old, height is measured while they are lying down (recumbent length). For children 2 years and older, height is measured while they are standing up. Standing height is typically about 0.7 cm less than recumbent length.