Height Calculator

How to read a child height estimate

A height calculator can be useful when a parent wants a simple way to organise family measurements and understand what they might suggest about future growth. It cannot know the exact timing of puberty, the effect of illness, the role of nutrition, or the many genes involved in height. For that reason, this tool gives a planning range instead of presenting one number as a promise. The range is intended to help you ask better questions and track changes over time.

The first estimate on this page is based on the mid-parental height approach. This uses the heights of both parents to create a family-height target. The second estimate starts from the child's current height relative to a broad age reference. The page blends those two views so neither one is treated as the whole story. A child can be healthy at many different points on a growth chart, especially when their measurements remain broadly consistent over time.

For the most useful result, measure height without shoes on a flat floor, with the back straight and eyes looking forward. Small measuring differences can noticeably change a prediction, especially for younger children. Record the date with every measurement so you can compare like with like rather than relying on memory.

The mid-parental height formula

The mid-parental method is a family-based estimate. For boys, add both parental heights, add 13 centimetres, and divide by two. For girls, add both parental heights, subtract 13 centimetres, and divide by two. The adjustment reflects the average adult-height difference used by this traditional screening formula. It is best treated as a centre point for discussion rather than a final answer.

Family height is important, but it does not explain everything. Brothers and sisters can finish at different heights. A child may inherit a mixture of traits from grandparents and other relatives. In addition, the age at which puberty begins can make one teenager look much taller or shorter than peers for several years without determining where their adult height will finally settle.

Why current growth matters too

Looking only at parental height misses useful context. A child who is currently taller or shorter than a broad age reference may follow a different path from the family target for a period of time. That is why this tool includes a current-growth estimate beside the mid-parental calculation. It compares present height with an illustrative age and sex reference, then translates the result into an adult-height projection.

This is still an estimate. Growth is not perfectly smooth. Children often grow in bursts, and adolescence can produce rapid changes in both height and body proportions. One annual measurement is less informative than several accurate measurements gathered across months or years. Health professionals typically review a sequence of measurements because the direction and pace of change can matter more than one isolated percentile.

Percentiles, growth patterns, and healthy variation

A percentile describes where a measurement sits within a reference group. For example, an adult-height comparison around the 50th percentile is near the middle of the chosen reference distribution. It does not mean “better” or “healthier” than another value. Percentiles are descriptive tools, not grades. A lower or higher percentile can be completely normal for a person with a stable growth pattern and a family history that matches it.

The adult comparison on this page is intentionally broad. It is not a child growth-chart percentile and should not replace a clinician's age-specific chart. For a child, the most helpful question is usually whether their height, weight, development, and general wellbeing are moving in a pattern that makes sense over time. Concerns are more relevant when a child changes direction sharply, develops symptoms, or has a persistent mismatch between growth and overall health.

When professional advice is important

Speak with a qualified health professional if a child appears to stop growing for a long period, crosses growth-chart percentiles quickly, has a major difference between expected and observed development, or has symptoms such as chronic fatigue, digestive concerns, frequent illness, pain, or unexplained weight changes. A clinician can review medical history, puberty timing, nutrition, family growth patterns, and accurate measurements together.

This is especially important when there is a known long-term condition, use of medication that can affect growth, a history of premature birth, or concern about early or delayed puberty. A calculator is useful for learning and record keeping, but it cannot perform an examination, assess bone age, or identify a cause behind an unusual growth pattern.

Height unit conversion made simple

Height is commonly recorded in centimetres in medical settings, while feet and inches remain common in everyday conversation in several countries. One inch equals 2.54 centimetres, one foot equals 12 inches, and one metre equals 100 centimetres. The conversion tab keeps all common formats connected so you can enter the unit you know and read the equivalent values immediately.

When converting feet and inches, remember that the inches field is not a decimal part of a foot. For example, 5 ft 6 in is not the same as 5.6 ft. The calculator handles that distinction automatically and gives both the familiar feet-plus-inches format and total inches for clear comparisons.