The tallest people in the world

Robert Wadlow, still unmatched

The tallest human being whose height is properly documented is Robert Pershing Wadlow, an American born in 1918. He reached 272 cm - 8 ft 11.1 in - and was measured by Guinness World Records during his own lifetime, which is the standard the record still rests on. He died in 1940 at the age of 22.

What makes Wadlow's record so durable is not just the number but the verification. He was measured in person, repeatedly, by an organisation with an interest in getting it right, and those measurements survive. Very few extreme-height claims from before the twentieth century can say the same.

The verified list is short

Most people assume there must be dozens of humans who have passed eight feet. There are not. The list of people with well-documented heights above 8 ft is short enough to name one by one, and once you get past about 8 ft 5 in it shrinks to a handful - half of which are disputed rather than confirmed.

Figures are the commonly cited values; the verification column reflects whether the height was accepted by a body such as Guinness World Records, which requires measurement under controlled conditions. Historical entries from before standardised records are inherently less certain.

Why extreme height usually has a cause

Height is polygenic - hundreds of variants each contribute a little - which is why most very tall people are simply at the top of an ordinary distribution. The extreme end is different. Above roughly 8 feet, the usual cause is an overproduction of growth hormone, typically from a pituitary adenoma.

That mechanism explains the pattern in the list. Growth hormone excess does not stop at the skeleton. It enlarges the heart, stresses joints that were never load-tested at that scale, and frequently causes chronic pain and mobility loss. Many of the people on this list died young, and almost all of them dealt with serious health problems. Extreme height is not a benefit; it is a medical condition with visible consequences.

What the growth curve does at the extremes

Adult height sits close to a normal distribution, with a mean around 171 cm for men and a standard deviation of roughly 7 cm. That curve predicts about 3 in 100,000 men above 200 cm. But it predicts effectively nobody above 250 cm - and the handful of people who are there are almost all explained by a hormonal cause rather than by the tail of the normal curve. This is why extreme height is described clinically, not statistically.

How a height record is actually verified

Guinness's procedure is unglamorous. The subject is measured against a stadiometer or a wall-mounted scale, barefoot with heels, buttocks and the back of the head against the vertical, typically at a consistent time of day, with an adjudicator present and photographic or video documentation. Repeat measurements on separate occasions are normal. The whole point is to remove the three things that inflate a height: shoes, posture and wishful rounding.

That is also, incidentally, exactly how you should measure anyone - which is the subject of our guide to comparing heights accurately.

See it for yourself

Numbers at this scale are hard to picture. The board below puts Wadlow, Sultan Kosen and a 178 cm adult on the same ruler; the difference between a very tall person and a record holder is considerably larger than most people expect.