Hello how may I help you? I need to know who the worlds tallest man is Sultan Kosen is the world's tallest man at 8 ft 3 inches is he alive? yes how tall is the average person? The average American height for men is 177 cm or 69.7 inches, which is approximately 5 foot 10 inches tall. who is the shortest perason? Chandra Bahadur Dangi, at 21 inches the shortest adult ever verified by Guinness World Records Wow. Thank you. Your are welcome