Where our numbers come from.

Height statistics disagree with each other more than most people expect. Two reputable sources can report the average American man as 176.9 cm and 175.3 cm and both be correct, because they are not measuring the same thing. This page explains exactly which figures Height Lens uses, what they measure, and where they stop being reliable.

Country averages

The 55 country figures behind our average height by country table and every percentile on the site come from the NCD Risk Factor Collaboration's 2020 pooled analysis in The Lancet. That study reports the mean height of 19-year-olds in 2019, drawn from 2,181 population-based studies covering 65 million people.

Nineteen is used because it is roughly when growth finishes, so it captures a generation at its full height. It is the series behind almost every "tallest countries" ranking you have seen. But it is not a country's average adult height, and conflating the two is the single most common error in this subject.

Why our US figure differs from the CDC's

We list the average American man at 176.9 cm (5′ 9.5″). The CDC, using measured data from NHANES 2015–2018, reports 175.3 cm (5′ 9″) for men aged 20 and over. That is a gap of 1.6 cm, and it is not an error in either number. Three things explain it:

• Age range. Ours is a single age (19). The CDC's spans everyone over 20, including people in their eighties.
• Generational change. Older adults in the CDC sample were born decades earlier, when average heights were lower. Including them pulls the mean down.
• Height loss with age. People lose height from roughly their forties onward, which pulls it down further.

Use the 19-year-old series when comparing countries, because it compares like with like. Use the CDC series when you want to know how you compare with adults you actually meet in the United States. For reference, here is the CDC's measured distribution for US men aged 20 and over:

Mean 175.3 cm, standard error 0.19, from 5,092 examined men. Women aged 20 and over: mean 161.3 cm (5′ 3.5″), from 5,510 examined women.

How percentiles are calculated

A percentile is the share of a reference group shorter than a given height. We convert a height into a z-score —(height − mean) ÷ standard deviation — and read it off a normal distribution. We assume a standard deviation of 7.1 cm for men and 6.5 cm for women, which are typical values for adult populations.

Three limits worth knowing:

• The standard deviation is assumed, not measured per country. Real spread varies between populations, so percentiles far from the average are the least reliable.
• Real height distributions are not perfectly normal. They are close enough in the middle and drift at the extremes, so a "99th percentile" result should be read as "very tall", not as a precise rank.
• Percentiles are shown for adults only. Children's height is assessed against age-specific growth charts, which is a different calculation, so we decline to give a number rather than give a misleading one.

The world figures we compare against are 171 cm for men and 159.5 cm for women. You can run any height through this yourself with the height percentile calculator.

How well a height is known

Not every figure on this site is evidenced to the same standard, and flattening them into one label would be dishonest in both directions. Every person page states which of three tiers its number belongs to:

• Measured — an identified party physically measured the person and published it with a date.Robert Wadlow is the clearest example on the site: 272 cm, taken by an anatomy professor on 27 June 1940, eighteen days before he died. Sultan Kösen and Jyoti Amge were both measured by Guinness World Records.
• Officially listed — an organisation publishes it, but as a listing rather than a measurement you can inspect. NBA roster heights sit here, and the era matters: the league only required barefoot measurement from the 2019–20 season, so earlier listings such as Yao Ming's may include shoes.
• Commonly reported — press and agency figures, which is most of the database. These routinely disagree by several centimetres for the same person.

Celebrity heights

The 69 heights in our celebrity database are commonly reported figures, not measurements. Nobody is measuring actors with a stadiometer. Published heights come from agency profiles, interviews and press materials, and they routinely disagree by two to five centimetres — sometimes more, when a figure is flattering rather than accurate.

We round to the nearest centimetre, present every value as reported rather than confirmed, and treat a celebrity height as a starting point for a comparison rather than a fact. If you have a well-sourced correction, we want it.

If you are measuring yourself to compare against any of this, the method matters as much as the maths —how to measure your height accurately covers the protocol these surveys use, including why you are up to 2 cm shorter by the evening.

Rounding and precision

• Country averages are shown to 0.1 cm, matching how the source publishes them.
• Celebrity heights are rounded to the nearest whole centimetre.
• Feet and inches are rounded to the nearest half-inch, which is finer than most sources report.
• Figures in the chart are drawn from the exact value you enter, so a one-centimetre difference is a real, to-scale one-centimetre difference on screen.

What this is not

Height Lens is built for curiosity, design work and settling arguments. It is not medical advice. Nothing here should be used to assess growth, diagnose a condition, or make a health decision. If you are worried about a child's growth, a clinician with the right growth charts is the person to ask.

Sources

• NCD-RisC (Lancet, 2020) — Mean height of 19-year-olds, by country and sex, 2019.
• CDC / NHANES 2015–2018 — Measured standing height of US adults aged 20 and over, 2015–2018.
• NCD-RisC (eLife, 2016) — Mean adult height by birth cohort, 1896–1996, in 200 countries, Birth cohorts 1896–1996.

NCD Risk Factor Collaboration (NCD-RisC). Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants. The Lancet. 2020;396(10261):1511–1524. · Fryar CD, Carroll MD, Gu Q, Afful J, Ogden CL. Anthropometric reference data for children and adults: United States, 2015–2018. National Center for Health Statistics. Vital and Health Statistics. 2021;3(46). · NCD Risk Factor Collaboration (NCD-RisC). A century of trends in adult human height. eLife. 2016;5:e13410.

Corrections

Found a number that looks wrong? Tell us what it should be and where that comes from, and we will check it: hello@heightlens.com. Corrections are made to the data, not buried in a footnote.