Height Calculator
Estimate how tall a child may grow from both parents' heights, with the mid-parental height formula pediatricians use and the range most children end up in.
Measure both parents if you can. Remembered heights can make the estimate too high or too low.
Predicted adult height for a girl
About 5 ft 4½ in
Most children end up between 5 ft 0½ in and 5 ft 8½ in, within 4 inches of this mid-parental height.
| Father's height | 70 in |
|---|---|
| Mother's height | +64 in |
| Subtract 5 in for a girl | −5 in |
| Sum | 129 in |
| Divided by 2: mid-parental height | 64.5 in |
| Target range, ± 4 in | 60.5 in to 68.5 in |
This is general information, not medical advice. Talk to a doctor about your own numbers.
How this is calculated
The mid-parental height is the average of the parents’ heights, adjusted for the child’s sex: men are on average taller, so the formula adds 5 inches (13 cm) for a boy and subtracts 5 inches for a girl before dividing by two. Family doctors and pediatricians use it to judge whether a child’s growth fits the family.
Boys: (father’s height + mother’s height + 5 inches) ÷ 2.
Girls: (father’s height + mother’s height − 5 inches) ÷ 2.
Example with a father of 5 feet 10 inches (70 inches) and a mother of 5 feet 4 inches (64 inches): for a boy, (70 + 64 + 5) ÷ 2 = 69.5 inches, or 5 ft 9½ in; for a girl, (70 + 64 − 5) ÷ 2 = 64.5 inches, or 5 ft 4½ in. In centimeters, with parents of 178 and 163 cm, a boy’s target is (178 + 163 + 13) ÷ 2 = 177 cm.
The range
Most children end up within 4 inches (10 cm) of their mid-parental height, which is two standard deviations, according to American Family Physician. The American Academy of Pediatrics puts it as 95 of 100 children. For the boy above that is 5 ft 5½ in to 6 ft 1½ in.
Limits
The formula only looks at the parents. It cannot know about nutrition, illness or an early or late puberty, which also shape growth. It works with the biological parents’ heights, and measured heights are better than remembered ones: American Family Physician advises measuring the parents to avoid over- or underestimating the target.
A doctor judges growth from the child’s own measurements over time: at least two, three to six months apart and preferably six to twelve. When a child’s projected height differs from the mid-parental height by more than 10 cm (4 inches), American Family Physician says that suggests a possible medical cause worth checking. If you are worried, talk to your pediatrician.
Sources
Checked against the sources below on .
- Barstow C, Rerucha C: Evaluation of Short and Tall Stature in Children. American Family Physician 2015;92(1):43–50, Table 1 (midparental height)
- Nwosu BU, Lee MM: Evaluation of Short and Tall Stature in Children. American Family Physician 2008;78(5):597–604 (measure the parents)
- American Academy of Pediatrics (EQIPP, Growth course): Mid-parental Height, target range ± 4 inches
Questions people ask
How tall will my son be?
Add the father's and mother's heights, add 5 inches and divide by 2. With a 5 ft 10 in father and a 5 ft 4 in mother: (70 + 64 + 5) ÷ 2 = 69.5 inches, about 5 ft 9½ in. Most boys end up within 4 inches of that.
How tall will my daughter be?
Add both parents' heights, subtract 5 inches and divide by 2. With a 5 ft 10 in father and a 5 ft 4 in mother: (70 + 64 − 5) ÷ 2 = 64.5 inches, about 5 ft 4½ in, give or take 4 inches.
How accurate is the mid-parental height?
It gives a target range, not an exact height. About 95 of 100 children end up within 4 inches (10 cm) above or below it, according to the American Academy of Pediatrics.
Can a child be taller than both parents?
Yes. The range reaches 4 inches above the target: a boy with a 5 ft 10 in father and a 5 ft 4 in mother may reach 6 ft 1½ in.
When should I worry about my child's height?
Ask your pediatrician. American Family Physician says a projected height more than 10 cm (4 inches) from the mid-parental height suggests a possible medical cause, and doctors judge growth from measurements six to twelve months apart.