Mid-parental height calculator

What is mid-parental height?

Mid-parental height is the simplest and most widely used way to estimate how tall a child will be as an adult. It's based on a well-established fact: children tend to end up near the average of their parents' heights, once you allow for the difference between men and women. Paediatricians call the result the child's target height, and they use it to judge whether a child's growth is on track for their family. The method was popularised by the British growth researcher J. M. Tanner, and it's still the first estimate most doctors reach for.

The midparental height formula

• For a boy: (mother's height + father's height + 13 cm) ÷ 2
• For a girl: (mother's height + father's height − 13 cm) ÷ 2

The 13 cm (about 5 inches) is the average difference in adult height between men and women. Adding it gives the mother's height "as if she were a man" for a son; subtracting it gives the father's height "as if he were a woman" for a daughter. In inches, use 5 instead of 13: a boy's target is (mother + father + 5) ÷ 2.

This mid-parental height calculator does that for you, in whichever units you type, and shows the result in both feet and centimetres.

The target height range: ±8.5 cm

A single number is only half the answer. Around 95% of children finish within 8.5 cm (3.3 inches) above or below their mid-parental height, so the calculator also shows that range. A son with a target of 177 cm will most likely end up somewhere between 168.5 and 185.5 cm. Doctors pay attention when a child's growth curve points well outside that band - it can be a sign that something other than genes is affecting growth.

Mid-parental height chart for boys

Predicted adult height for a son, by the mother's height (rows) and the father's height (columns):

Mid-parental height chart for girls

Predicted adult height for a daughter, by the mother's height (rows) and the father's height (columns):

A worked example

The mother is 5′ 4″ (162.6 cm) and the father is 5′ 10″ (177.8 cm). For a son: (162.6 + 177.8 + 13) ÷ 2 = 176.7 cm, about 5′ 9½″, with a target range of roughly 168 to 185 cm. For a daughter: (162.6 + 177.8 − 13) ÷ 2 = 163.7 cm, about 5′ 4½″, with a range of roughly 155 to 172 cm.

How doctors use the midparental height calculator

Paediatricians plot a child's height on a growth chart at every check-up. The mid-parental height tells them which part of the chart the child is expected to follow. A child who is short but tracking steadily toward a short family's target is usually fine; a child who is dropping across percentile lines, or heading far outside the target range, may need a closer look. That's why the number is most useful as part of a series of measurements rather than on its own.

Why we built this mid-parental height calculator

Before building CheckMyHeight, I tested a lot of height and sizing websites to see what people need and what gets in the way. For "how tall will my child be", two things kept getting in the way. Many predictors give a single number, while the method's own research says most children land somewhere in a band about 17 cm wide, so a single number promises more than the method can deliver. And most rely on parents' heights typed from memory, although adults often round their height up, which shifts the prediction directly.

So this page shows the target range next to the target height, prints the formula with your numbers in it, and lets you measure either parent with the phone camera instead of guessing.

What this mid-parental height calculator measures

It takes three inputs: the child's sex and the mother's and father's heights, typed in centimetres, metres or feet and inches (for example 163, 1.63 or 5'4), or measured with the camera button next to each box. Then it does exactly this:

• Boy: (mother + father + 13 cm) ÷ 2. Girl: (mother + father - 13 cm) ÷ 2. The 13 cm is the average adult height difference between men and women, as in Tanner's method.
• Target range: the result plus and minus 8.5 cm, the band that about 95% of children finish in.
• The working is printed under the result, in centimetres, so you can check the sum yourself.

The formula and the ±8.5 cm range were last checked on 24 October 2026 against the sources in the guide. What it does not measure: the child's own height, weight, age or bone age, puberty timing, health or nutrition, all of which move real adult height. For a prediction that also uses a toddler's height, use the height calculator. It is an estimate, not medical advice.

Why this mid-parental height calculator is different

• A range, not just a number, because that is what the method supports.
• Measure the parents with the phone camera rather than relying on remembered heights.
• The formula is shown with your own numbers, plus quick-look charts for boys and girls.
• Any units: centimetres, metres or feet and inches, with the answer in both.
• No account and nothing sent. The sum runs in your browser and the heights are not stored.
• Both height boxes start empty, and no result shows until both are filled in.

When the prediction is less reliable

• Estimated parent heights. Many adults round up their height. Measuring both parents - the 📏 buttons use your phone camera - makes the result noticeably better.
• Very different parents. When one parent is much taller than the other, children can take after either, so the range matters more than the middle.
• Changing generations. Average heights have risen over the last century as nutrition improved, so children can end up taller than their parents' figures suggest.
• Health and puberty. Long-term illness, some medicines, and very early or late puberty all shift adult height.

Mid-parental height vs other height calculators

The mid-parental method needs only the parents' heights, which makes it perfect for babies and young children. Other methods add the child's own measurements: the age-2 method doubles a toddler's height, and clinical methods such as Khamis-Roche combine the child's current height, weight and age with the parents' heights. Bone-age methods, based on a hand X-ray, are the most precise and are used by specialists. For everyday curiosity, the mid-parental height calculator is the best balance of simplicity and accuracy.

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