Hair typically grows at an average rate of about half an inch (approximately 1.3 cm) per month, or roughly 6 inches (about 12.7 cm) per year
. This rate can vary depending on factors such as age, genetics, ethnicity, diet, hormones, and overall health
. Hair growth occurs in cycles consisting of three main phases:
- Anagen phase (growth phase): Lasts between 2 to 6 years, during which hair actively grows at about 1 cm per month on average. The length of this phase determines how long hair can grow
- Catagen phase (transition phase): A short phase lasting about 2 to 3 weeks where hair growth slows and the follicle shrinks
- Telogen phase (resting and shedding phase): Lasts about 3 months, during which hair follicles rest and old hairs shed before new growth begins
Because hair grows in cycles and not all hairs are in the same phase simultaneously, the visible growth rate is an average across all hairs. In summary, under healthy conditions, hair grows about half an inch per month, but the total time it takes for hair to grow a certain length depends on the duration of the anagen phase and individual factors affecting growth
