split image of Robert Wadlow

When Robert Wadlow was born on 22 February 1918 to average-sized parents, weighing an unremarkable 3.85 kg (8.7 lb), there was no indication that he would go on to become the world’s tallest man ever.

However, as a toddler, he began growing rapidly and he never stopped.

By the age of five, he stood at a height of 1.63 m (5 ft 4 in), already wearing clothes intended for teenagers.

He hit the six-foot mark (1.83 m) when he was just eight years old, outgrowing his father, Harold F. Wadlow, whom Robert could now carry up the stairs of their home.

Robert continued growing at a remarkable rate: at age nine he was 1.89 m (6 ft 2 in) and at age 10 he measured 1.96 m (6 ft 5 in), the same height as Dwayne “The Rock” Johnson. Robert weighed 95 kg (210 lb) at this young age.

By age 11, he had reached the incredible height of 2.00 m (6 ft 6.7 in), almost an inch taller than legendary basketballer Michael Jordan. He then grew a whopping 10 cm in one year, measuring 2.10 m (6 ft 10.6 in) when he was 12.

13-year-old Robert Wadlow towering over his father

Robert didn’t let his size stop him from participating in the same activities as his classmates. He became a Boy Scout when he was 13, requiring a custom-made uniform, sleeping bag and tent. He weighed 116 kg (255 lb) and measured 2.18 m (7 ft 1.8 in), which is over one inch taller than Rumeysa Gelgi, the current tallest woman living.

Robert’s unprecedented height led to several medical issues during his teen years, which only worsened as he grew older. When he was 14 – standing at a height of 2.26 m (7 ft 5 in) – he slipped while playing in the street, breaking two of the bones in his foot. From then on, Robert was required to wear an ankle brace to support his sizeable stature.

He grew a further 8 cm (3.1 in) over the course of that year, measuring 2.34 m (7 ft 8 in) by age 15, which is two inches taller than Yao Ming, the iconic Chinese basketballer. Robert had gained 100 lb in just two years, now weighing 161 kg (355 lb).

At 16 years old, Robert was 2.40 m (7 ft 10 in) tall, and at 17 he hit the eight-foot mark (2.45 m), becoming the tallest teenager ever. It was during this year that he was hospitalized due to an infection caused by a shoe pad, requiring eight men and a reinforced stretcher to carry him to the hospital.

The foot infection, in addition to a bout of severe influenza, caused Robert’s weight to drop from 170 kg (374 lb) to 143 kg (315 lb).

Robert Wadlow, age 18, standing next to his 14-year-old brother, Eugene

After graduating high school in 1936, 18-year-old Robert enrolled in college to study law. However, later that year, he decided to instead go on tour with the Ringling Brothers Circus, gaining international fame. He measured 2.53 m (8 ft 3.6 in), almost one inch taller than Sultan Kösen, the current tallest man living.

At age 19, Robert hit the heady height of 2.58 m (8 ft 5.5 in), one centimetre taller than the reported heights of Hồ Văn Trung (Vietnam, 1984-2019) and Pornchai Saosri (Thailand, 1989-2015), who were two of the tallest men to have existed in the 21st century, although their heights were never officially verified by Guinness World Records. Robert now weighed 218 kg (480 lb), over 50% heavier than he was two years earlier.

Robert’s height was 2.61 m (8 ft 6.7 in) when he was 20, and at 21 he reached 2.65 m (8 ft 8.3 in), one centimetre taller than John F. Carroll (USA, 1932-1969), the third-tallest man ever. Consuming up to 8,000 calories per day, Robert reached his peak weight of 223 kg (491 lb) at this age.

Over the next year, he grew taller than John “Bud” Rogan (USA, 1868-1905), who measured 2.67 m (8 ft 9 in) and was the tallest man ever until Robert overtook him. Rogan remains the second-tallest man in history.

Robert Wadlow standing in a hotel lobby in St. Petersburg, Florida, one day after his 22nd birthday

Sadly, aged 22 years 5 months old, on 15 July 1940, Robert passed away due to a septic blister on his right ankle. The wound was caused by a poorly fitted iron brace which he wore to support his long leg.

Robert’s terminal illness caused his weight to drop to 199 kg (439 lb), although his height continued to increase up until the day he died. Robert reached a peak height of 2.72 m (8 ft 11.1 in), which is taller than an average grizzly bear standing on its hind legs.

Robert’s extreme height was caused by hyperplasia of his pituitary gland, which produced an abnormally high level of human growth hormone.

Although his hypertrophic pituitary gland was identified by doctors, they advised Robert and his family against having it surgically removed due to the high risk of death.

Nowadays, with modern medical technology, we can safely slow or halt excessive growth, which is why it’s unlikely that anyone will ever grow as tall as Robert Wadlow.

Want more? Follow us across our social media channels to stay up-to-date with all things Guinness World Records! You can find us on Facebook, Twitter, Instagram, ThreadsTikTok, LinkedIn, and Snapchat Discover.

Don’t forget, we’re also on YouTube!

Still not had enough? Follow the link here to buy our latest book, filled to the brim with stories about our amazing record breakers.