Maximum hair length

The maximum hair length that is possible to reach is about 15 cm (6 in) for infants (below the age of 1), about 60 cm (24 in) for children (below the age of 13), and generally 100 cm (40 in) for adults. Documentation for decrease of the maximum length with age cannot be found in the literature. Some individuals can reach excessive lengths. Lengths greater than 150 cm (59 in) are frequently observed in long hair contests. Xie Qiuping had the longest documented hair in the world, measuring 5.627 m (18 ft 5.54 in) in May 2004. 

The maximum terminal hair length depends on the length of the anagen (period of hair growth) for the individual. Waist-length hair or longer is only possible to reach for people with long anagen. The anagen lasts between 2 and 7 years, for some individuals even longer, and follows by shorter catagen (transition) and telogen (resting) periods. Between 85% and 90% of the hair strains are in anagen.