A Free Alternative for Predicting Adult Height
If you searched for a GoTall alternative, you may simply want a height estimate you can use now. Our calculator is free, requires no registration, and shows your result immediately. Instead of presenting one exact-looking number as a certainty, it gives a likely adult-height range and explains the calculation behind it. This page describes only what our own tool does, how to use it, and where its limits begin.
Not affiliated with or endorsed by GoTall.
What this free height predictor does
The calculator estimates adult height for people aged 8 to 20. It asks for sex, age, current height, both parents' heights, and pubertal stage. Those inputs cover three useful signals: the height pattern in your family, how tall you already are for your age, and roughly how much of the normal growth sequence may be behind you.
The result is an estimate, not a measurement of future height. You see a central prediction in centimetres and feet and inches, surrounded by a likely range. The range matters because two people with similar inputs can still finish at different heights. Genes are inherited in different combinations, pubertal timing varies, and self-reported measurements are never perfectly exact.
Start the tool at the top of this page and answer the prompts. The result appears without an account and identifies the inputs and method used.
How the estimate works
The calculation blends two methods. The first is the mid-parental height formula, a family-based starting point. It averages the two parents' heights, then adds 6.5 cm for a male estimate or subtracts 6.5 cm for a female estimate. This gives the centre of a broad genetic target range; it cannot identify the particular combination of height-related variants one person inherited.
The second method projects current height forward using age- and sex-based growth fractions, with an adjustment for the pubertal stage you select. In plain language, it asks what share of adult height is usually complete at that point in development, then uses your present height to estimate the remaining share.
When current height and age are available, our calculator gives the mid-parental estimate 55% of the weight and the current-height projection 45%. Combining the two prevents either family history or one present-day measurement from deciding the result alone. The tool also keeps the adult estimate from falling below a trajectory implied by the height already reached.
The interval around the central estimate is calculated separately. It becomes wider for younger users, when current-height information is missing, and when the family-based and current-height methods disagree. It becomes narrower when more growth is already complete and the two methods point in a similar direction. That changing width is part of the answer: it reflects how much uncertainty the available inputs leave.
What you get
- A predicted adult-height range. The central estimate is shown with lower and upper bounds in both metric and imperial units.
- A calculation summary. The result states that it blended mid-parental height with a current-height projection and lists the inputs used.
- An uncertainty explanation. The displayed range width changes with age, input completeness, and disagreement between the two methods.
- An age boundary. The method is intended for ages 8–20; outside that range the estimate is unreliable.
- General healthy-growth guidance. The result includes broad reminders about nutrition, activity, posture, and sleep. These are general suggestions, not a diagnosis or a personalised treatment plan.
How to use it
Begin with measurements taken as carefully as you can. Measure current height without shoes, on a hard floor, with heels against a wall and eyes level. Height changes slightly through the day as the spine compresses, so use a consistent time if you plan to compare the result with a later measurement. Enter both parents' adult heights from measured values where possible rather than estimates from memory.
Choose the pubertal stage that most closely describes where you are now. People of the same age can be at different points in growth, but the selection remains subjective. Read the range and method notes together, and rerun the estimate if a measurement was wrong.
What it can't do
This calculator is a statistical estimator, not an instrument that measures future height. Its formulas describe common growth patterns across groups. They cannot see your genes, growth plates, bone age, medical history, or individual growth curve, and they cannot know the exact timing of your remaining growth.
The model has not been validated against a clinical dataset. Its output should be treated as an educational estimate, not as a clinically tested prediction for an individual.
Self-reported inputs introduce error. A small mistake in current height, a parent's height remembered incorrectly, or a pubertal stage chosen too early or too late can shift the result. The interval reflects some uncertainty in the calculation, but it is not a guarantee that final height will fall inside it.
The tool cannot diagnose delayed puberty, growth hormone deficiency, thyroid disease, coeliac disease, or any other cause of unusual growth. It also cannot confirm whether growth plates are open. A clinician can review measurements over time and, when appropriate, use an examination, tests, or a hand and wrist X-ray. If your growth has slowed unexpectedly, you are crossing downward through growth-chart percentiles, or pubertal development seems unusually early or late, speak to a parent or carer and a paediatrician.
How to read your result responsibly
Treat the middle value as a convenient centre, not a destination your body is required to reach. The lower and upper bounds are equally important. A wide interval means the inputs leave substantial uncertainty; it is not a poor score. A narrow interval still does not create certainty.
One result is less useful than a reliable height record over time. If you are still growing, measure under the same conditions and track the change across six to twelve months. Recent growth, shoe and trouser-size changes, and pubertal timing can help you understand where you are in the sequence, but none proves a final height on its own. For a broader guide written for people estimating their own growth, visit the teen height guide.
Frequently asked questions
Is this height predictor free?
Yes. You can complete the calculator and see the adult-height estimate and likely range without creating an account or paying. The result appears immediately after you finish the prompts.
What information do I need to enter?
The main inputs are sex, age, current height, both parents' adult heights, and pubertal stage. Accurate measurements help, but every self-reported input can add uncertainty.
How is the adult-height estimate calculated?
The calculator blends a mid-parental height estimate with a projection from current height, age, sex, and pubertal stage. When both are available, the family-based estimate receives 55% of the weight and the current-height projection 45%.
Why does the result show a range?
Height prediction is uncertain. The range becomes wider for younger users, missing current-height data, and disagreement between the two methods. It narrows when development is further along and the methods are closer.
Can this result replace a doctor's assessment?
No. The model has not been validated against a clinical dataset and cannot examine growth history, bone age, health, or growth plates. If you are concerned about growth or puberty, ask a paediatrician.
This page provides general educational information, not medical advice, diagnosis or treatment. The estimate cannot predict a specific outcome. If you are concerned about your growth, speak to a paediatrician or family doctor, ideally with a parent or carer involved.