Height Calculator
Predict a child's adult height from both parents' heights, with the expected range and the working.
Doubling check (optional)
Halfway between the parents' heights, plus 2.5 in for a boy.
Bright band: expected range. Mother 5 ft 4 in, father 5 ft 10 in.
Expected adult height range
Tanner's range of 8.5 cm (3.3 in) either side of the target spans the 3rd to 97th percentiles, so about 94 in 100 children finish inside it.
Your calculation
The same steps the calculator runs, with your numbers.
- Convert: father 5 ft 10 in = 70 in, mother 5 ft 4 in = 64 in.
- Add the parents: 70 + 64 = 134 in.
- Boy: add 5 in: 134 + 5 = 139 in.
- Divide by 2: 139 รท 2 = 69.5 in = 5 ft 9.5 in.
- Range: 69.5 ยฑ 3.3 in (8.5 cm) = 5 ft 6.2 in to 6 ft 0.8 in.
Family and reference heights
Your inputs beside the other estimates and the US adult averages.
| Height | Feet and inches | Centimeters |
|---|---|---|
| Father | 5 ft 10 in | 177.8 cm |
| Mother | 5 ft 4 in | 162.6 cm |
| If the child were a girl | 5 ft 4.5 in | 163.8 cm |
| Doubling check | Not entered | โ |
| US average man (CDC) | 5 ft 8.9 in | 175.0 cm |
| US average woman (CDC) | 5 ft 3.5 in | 161.3 cm |
An estimate from the parents' heights only. Growth, nutrition and health also shape adult height, so ask your child's doctor about any growth concerns.
How the Height Calculator Works
This height calculator estimates how tall a child will be as an adult from the heights of both parents. It uses the mid parental height, also called the target height, which Mayo Clinic describes as a way of making a guess at adult height. The method dates from growth standards published by Tanner and colleagues in 1970 and is still the starting point clinicians use when they compare a child's growth with family height.
Men are taller than women on average, so the formula shifts the parents' average up for a son and down for a daughter. Mayo Clinic gives the shift as 5 inches or 13 centimeters before halving, which works out to 2.5 inches or 6.5 cm. The calculator uses 5 inches in feet and inches mode and 13 cm in centimeter mode, so each result matches the textbook version of the formula in that unit.
The expected range is the target plus or minus 8.5 cm (3.3 inches). For the 180 cm and 165 cm parents, a son's range is 170.5 to 187.5 cm and a daughter's is 157.5 to 174.5 cm.
Predicted Adult Height Chart
Predicted adult height for a son by the parents' heights, using the mid parental formula in inches. For a daughter, subtract 5 inches from any value in the table, because the formula adds 2.5 inches for a boy and subtracts 2.5 inches for a girl.
| Mother โ Father โ | 5 ft 6 in | 5 ft 8 in | 5 ft 10 in | 6 ft 0 in | 6 ft 2 in |
|---|---|---|---|---|---|
| 5 ft 0 in | 5 ft 5.5 in | 5 ft 6.5 in | 5 ft 7.5 in | 5 ft 8.5 in | 5 ft 9.5 in |
| 5 ft 2 in | 5 ft 6.5 in | 5 ft 7.5 in | 5 ft 8.5 in | 5 ft 9.5 in | 5 ft 10.5 in |
| 5 ft 4 in | 5 ft 7.5 in | 5 ft 8.5 in | 5 ft 9.5 in | 5 ft 10.5 in | 5 ft 11.5 in |
| 5 ft 6 in | 5 ft 8.5 in | 5 ft 9.5 in | 5 ft 10.5 in | 5 ft 11.5 in | 6 ft 0.5 in |
| 5 ft 8 in | 5 ft 9.5 in | 5 ft 10.5 in | 5 ft 11.5 in | 6 ft 0.5 in | 6 ft 1.5 in |
Each 2 inches added to either parent adds 1 inch to the prediction, since the formula averages the two heights.
How Accurate Is a Height Prediction?
MedlinePlus Genetics, from the National Library of Medicine, explains that scientists estimate about 80 percent of a person's height comes from inherited DNA variation. Height is polygenic: hundreds of gene variants each add a small effect, which makes an exact prediction hard and explains why siblings can differ in height. Environmental factors such as nutrition make up the rest.
A 2024 study in the journal Children by Zeevi and colleagues found that mid parental height, corrected for sex the standard way, explained 36 percent of the variation in children's adult heights. The same paper notes that Tanner set the normal range at 8.5 cm either side of the target, matching the 3rd and 97th percentiles, and later widened it to 9 cm for girls and 10 cm for boys.
Things that shift the estimate
- Parents' ages. Adults lose height with age, so measured parent heights can be lower than their peak. The 2024 paper reports that Tanner suggested adding 1.5 cm for parents aged 45 to 55 and 3 cm for parents over 55.
- A fixed 13 cm sex gap. The same paper points out that the difference between male and female heights is not exactly constant across the height range, so very tall or very short parents add more error.
- Timing of growth. Mayo Clinic notes that children grow at different rates and some start their growth phases early while others start later.
The Doubling Method
Mayo Clinic describes a second rule of thumb: double a boy's height at age 2, or a girl's height at 18 months. It needs only one measurement of the child, so it works when a parent's height is unknown.
Enter the measurement in the Doubling check box to see this estimate beside the mid parental result. When the two disagree by several inches, the range from the mid parental method is a better guide than either single number.
How to Use the Calculator
- Pick units. Choose feet and inches or centimeters. Switching converts the heights already entered.
- Choose boy or girl. This sets whether the formula adds or subtracts the sex adjustment.
- Enter both parents' heights. Use measured adult heights without shoes when you can.
- Add the doubling check if you have it. Enter the child's height at age 2 for a boy or 18 months for a girl.
The large number is the predicted adult height, with the other unit beside it. The card below gives the expected range, and the tiles show the parents' average, the sex adjustment and the difference from the US average adult of the same sex.
Common Mistakes
- Estimating a parent's height. A guess that is 2 inches off moves the prediction by 1 inch.
- Treating the result as exact. The range of 3.3 inches either side matters more than the single number.
- Mixing units. Converting 5 ft 10 in as 5.10 feet is wrong: 5 ft 10 in is 70 inches, or 5.83 feet.
- Expecting the two unit versions to agree exactly. 5 inches is 12.7 cm, not 13 cm, so the centimeter version runs 0.15 cm taller for a boy.
- Doubling at the wrong age. The rule uses age 2 for boys and 18 months for girls.
Height Conversion and US Averages
One inch is exactly 2.54 cm. NIST notes that the inch has been defined as exactly 25.4 mm since July 1, 1959. To convert feet and inches to centimeters, change the height to inches (feet ร 12 + inches) and multiply by 2.54: 5 ft 10 in = 70 in ร 2.54 = 177.8 cm.
| Feet and inches | Centimeters | Feet and inches | Centimeters |
|---|---|---|---|
| 4 ft 10 in | 147.3 | 5 ft 8 in | 172.7 |
| 5 ft 0 in | 152.4 | 5 ft 10 in | 177.8 |
| 5 ft 2 in | 157.5 | 6 ft 0 in | 182.9 |
| 5 ft 4 in | 162.6 | 6 ft 2 in | 188.0 |
| 5 ft 6 in | 167.6 | 6 ft 4 in | 193.0 |
The CDC reports measured average heights for US adults aged 20 and older of 68.9 inches (175.0 cm) for men and 63.5 inches (161.3 cm) for women, from national measurements taken from August 2021 to August 2023. The calculator compares each prediction with the average for the same sex.
Frequently Asked Questions
How tall will my child be?
A common estimate is the mid parental height. Add the mother's and father's heights, add 5 inches (13 cm) for a boy or subtract 5 inches (13 cm) for a girl, then divide by 2. This is the method Mayo Clinic describes for guessing adult height. Most children finish within about 8.5 cm, or 3.3 inches, of this target, the range Tanner set at the 3rd and 97th percentiles. There is no sure way to predict adult height, and growth, nutrition and health all play a part.
How accurate is the mid parental height formula?
It gives a reasonable center point but a wide range. In a 2024 study of families published in Children, mid parental height corrected the standard way explained 36 percent of the variation in children's adult heights. Tanner estimated that adult height should fall within 8.5 cm of the target for about 94 in 100 children, and later widened the range to 9 cm for girls and 10 cm for boys. Measured parent heights, parents' ages and the child's own growth all affect accuracy.
Can you predict adult height from height at age 2?
Mayo Clinic lists a second rule of thumb: double a boy's height at age 2 or a girl's height at 18 months. A boy who measures 34.5 inches at age 2 doubles to 69 inches, or 5 feet 9 inches. A girl who measures 31 inches at 18 months doubles to 62 inches, or 5 feet 2 inches. The rule is a rough guide only. Use it alongside the mid parental height, and ask your child's doctor to plot growth on a growth chart if you have concerns.
How tall will my son be if his father is 5 ft 10 in and his mother is 5 ft 4 in?
About 5 feet 9.5 inches. The father's 70 inches plus the mother's 64 inches is 134 inches. Adding 5 inches for a boy gives 139, and half of that is 69.5 inches, or about 176.5 cm. The expected range, 8.5 cm either side, runs from about 5 feet 6.2 inches to 6 feet 0.8 inches. A daughter of the same parents has a predicted height of 5 feet 4.5 inches, because the formula subtracts 5 inches for a girl instead of adding them.
Does height come from the mother or the father?
From both. MedlinePlus Genetics explains that height is polygenic, shaped by hundreds of gene variants inherited from both parents, and that scientists estimate about 80 percent of a person's height comes from inherited variation. The mid parental formula reflects this by giving each parent equal weight. Different combinations of variants explain why siblings can differ in height. Nutrition, health during childhood and other environmental factors account for the rest.
What is the average height for men and women in the US?
According to the CDC, the measured average height for adults aged 20 and older in the United States is 68.9 inches for men, about 5 feet 8.9 inches or 175.0 cm, and 63.5 inches for women, about 5 feet 3.5 inches or 161.3 cm. The figures come from national measurements taken from August 2021 to August 2023. This calculator compares the predicted adult height with the average for the same sex, so you can see whether the estimate sits above or below it.
Sources & References
- Mayo Clinic Staff. Child growth: Can you predict adult height? (mid parental formula, doubling at age 2 or 18 months), January 25, 2025. mayoclinic.org
- Tanner JM, Goldstein H, Whitehouse RH. Standards for children's height at ages 2 to 9 years allowing for heights of parents. Archives of Disease in Childhood, 1970. pubmed.ncbi.nlm.nih.gov
- Zeevi D, Ben Yehuda A, Nathan D, Zangen D, Kruglyak L. Accurate Prediction of Children's Target Height from Their Mid Parental Height. Children (Basel), 2024 (range of 8.5 cm, 36 percent of variance, age corrections). pubmed.ncbi.nlm.nih.gov
- MedlinePlus Genetics, National Library of Medicine. Is height determined by genetics? medlineplus.gov
- CDC National Center for Health Statistics. FastStats: Body Measurements (US adult average heights, 2021 to 2023), reviewed June 26, 2025. cdc.gov
- NIST. SI Units: Length (inch defined as exactly 25.4 mm since 1959). nist.gov
Results are for informational purposes only and should not be used as a diagnosis or substitute for professional medical advice. Every number on this page was recomputed with the same code the calculator uses. Methodology reviewed: 2026.