Height Calculator

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Use this height calculator to estimate adult height from parent heights or child data and to check current height percentile for age.

Estimate adult height from parent heights, or check current height percentile using CDC data.
CDC height percentiles and common target-height formulas are sex-specific.
For the percentile check, enter age in years. Decimals are allowed, such as 10.5.
Use feet and inches for US entries.
Enter the extra inches beyond the feet value.
Used only in the fuller estimate method.
Enter biological father height for the standard parent-based formulas.
Enter the extra inches beyond the feet value.
Enter biological mother height for the standard parent-based formulas.
Enter the extra inches beyond the feet value.
Advanced options

Precision

Optional. Helps match CDC age-by-month data more closely.

Display

Change only how results are shown. Calculations use the same underlying values.
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How to use our Height Calculator

  1. Choose the parent-height estimate or current height percentile.
  2. For the parent estimate, enter both parents' heights and the child's sex. For the percentile, enter the child's sex, age and current height.
  3. Enter height as feet plus inches. Advanced options let you add extra months to the entered age and change result units.
  4. Click Calculate. A current percentile compares height with peers of the same age and sex; it does not predict adult height.

Definitions

Estimated adult height: A mid-parent estimate using the heights of the biological parents.

Expected range: The target plus or minus 3.35 inches (8.5 cm), not a guarantee.

Current height percentile: A comparison using CDC stature-for-age data for the selected age and sex.

Common mistakes and quick fixes

Mistake: Entering total inches in the inches box.
Fix: Enter whole feet separately and use inches from 0 up to, but not including, 12.

Mistake: Treating a current percentile as a prediction of adult height.
Fix: Use the parent-height estimate for a rough adult target. The percentile describes current height only.

Mistake: Counting extra months twice.
Fix: If age already includes the fractional year, leave extra months at zero.

Limitations & Key Assumptions / Boundary Conditions

  • Parent-height estimates are approximate and do not account for puberty timing, health, nutrition or bone age.
  • CDC stature-for-age data covers ages 2 through 20 years. The reference population and the child's measurement method affect interpretation.
  • The parent estimate uses biological parent heights. The range is not a promise.
  • This tool does not offer the Khamis-Roche child-plus-parents prediction method.

Methodology

Parent-height estimate

Convert each parent's height to inches. For boys, target = (father + mother) / 2 + 2.5 inches. For girls, subtract 2.5 inches instead. The displayed range is target plus or minus 3.35 inches.

For a father of 70 inches and mother of 65 inches, the boy's target is 70 inches, or 5 ft 10 in.

CDC height-for-age percentile

Age in months equals entered years times 12, plus any extra months. Height is converted to centimetres. Sex-specific L, M and S parameters come from the CDC 2000 stature-for-age dataset; parameters are interpolated between adjacent tabulated ages.

z = ((height / M)^L - 1) / (L * S)

For L = 0, use z = ln(height / M) / S. The percentile is the standard normal cumulative probability at z, multiplied by 100. Reference data was retrieved on 13 September 2026.

Sources

  1. Growth Charts - Clinical Growth Charts - CDC
  2. Growth Charts - Percentile Data Files with LMS Values - CDC
  3. Predicting adult stature without using skeletal age: the Khamis-Roche method - PubMed - NIH
  4. Accurate Prediction of Children's Target Height from Their Mid-Parental Height - PMC - NIH