This futon comes in 3 sizes: Small (S), Medium (M) and Large (L).
The small size is 180cm long (5 feet, 11 inches); the medium size is 200cm (6 feet, 7 inches) and the large size is 210cm (6 feet, 11 inches).
You should choose a size that is about 10-15cm larger than your height. The width of the futon is half the height.