How Tall Will My Daughter Be?
Girls' growth follows a tighter, earlier schedule than boys' — which makes it easier to predict, and also means the window closes sooner. This page covers the formula for girls, how much growth is left after her first period, and why the tallest girl in Year 6 often isn't the tallest woman in the room fifteen years later.
The formula for a girl's adult height
The mid-parental method is the standard starting point, with the adjustment running the other way:
Daughter's adult height ≈ (father's height + mother's height) ÷ 2 − 6.5 cm
(subtract 2.5 inches if you're working in feet and inches)
If dad is 180 cm and mum is 166 cm, the estimate is (180 + 166) ÷ 2 − 6.5 = 166.5 cm, or about 5'5½". The 6.5 cm adjustment reflects the average adult height difference between women and men — it turns a family average into a female-specific figure.
Accuracy is typically within about 5 cm. The calculator above also uses her current height relative to her age, which matters more for girls than boys because so much of the growth is compressed into a short window.
The girls' growth timeline
| Age | What's happening | Typical gain per year |
|---|---|---|
| 4 – 9 | Steady childhood growth | 5 – 6 cm |
| 10 – 12 | Puberty begins, spurt starts | 6 – 9 cm |
| 11 – 13 | Peak height velocity, usually before first period | 7 – 9 cm |
| 13 – 16 | Growth slows sharply after first period | 2 – 4 cm, then stops |
The key structural difference from boys: a girl's growth spurt comes before her first period, not after. By the time menstruation begins, the fastest growing is already behind her.
How much growth is left after her first period?
This is the single most common question parents have, and it has a reasonably firm answer: most girls grow another 5 to 7.5 cm (2 to 3 inches) after their first period, and finish within about two years of it.
Timing shifts the number:
- Early first period (10–11) — usually more growth left, sometimes 8 cm or more, because she started the whole sequence sooner.
- Average (12–13) — the typical 5–7.5 cm.
- Late first period (14+) — often less remaining growth, because she was growing at a childhood rate for longer and then compressed the spurt.
Why the tallest girl in class often evens out
Between 11 and 13, a class of girls is a mix of those who have started puberty and those who haven't. The early developers are dramatically taller — not necessarily because they'll be tall adults, but because they got a two-year head start. They also stop growing first.
By 16 or 17 the ordering has usually rearranged. A girl who was a head above everyone at 11 and is merely average at 17 hasn't stopped growing early in any concerning sense; she simply front-loaded it. The mid-parental estimate cuts through this timing noise, which is why it is more informative than comparing her to her classmates.
When to speak to a doctor
- She grows less than about 4 cm a year between age 4 and the start of puberty.
- She drops across percentile lines on the growth chart instead of tracking one.
- No breast development by 13, or no first period by 15.
- Puberty signs before age 8 — early puberty can shorten the growth window and is treatable.
- She is far below the mid-parental estimate with no family history explaining it.
What helps her reach her potential
- Sleep — deep sleep is when growth hormone peaks. The spurt years and the years of heaviest schoolwork unfortunately overlap.
- Iron and overall nutrition — once periods start, iron needs rise, and under-fuelling during the spurt has a measurable cost.
- Activity, in balance — sport supports bone density. Very heavy training combined with under-eating can delay puberty and affect growth, which is worth watching in competitive gymnastics, dance and distance running.
↑ Run the free predictor for your daughter — 60 seconds, result shown without an account.
Frequently asked questions
How tall will my daughter be?
Add the father's and mother's heights, divide by two, then subtract 6.5 cm (about 2.5 inches). That mid-parental figure usually lands within 5 cm of the real outcome, and her current height for her age narrows it further.
How much will she grow after her first period?
Most girls grow another 5 to 7.5 cm (2 to 3 inches) and finish within about two years of it. Girls who start early tend to have more growth left; girls who start late tend to have less.
At what age do girls stop growing?
Most girls reach final adult height between 14 and 16, roughly two years after their first period, when the growth plates close.
When does a girl's growth spurt happen?
Usually between 10 and 14, peaking around 11 to 13, when she can add 6 to 9 cm in a year. The spurt typically begins before her first period, not after.
She's taller than everyone in her class — will she stay that way?
Often not by as much. Early developers are tall for their age at 11 or 12 but finish growing sooner, so classmates close the gap. Early height is partly a timing effect, not only a genetic one.
This tool provides a statistical estimate for general information only. It is not medical advice, diagnosis or treatment. If you are concerned about your daughter's growth, speak to a paediatrician or family doctor.