Hair typically grows at an average rate of about half an inch (approximately 1.27 centimeters) per month, which translates to roughly 6 inches (15 centimeters) per year

. This rate can vary depending on several factors including age, genetics, ethnicity, and hair thickness.

Key points about hair growth speed:

• Average Growth Rate: About 0.5 inch (1.27 cm) per month or 6 inches (15 cm) per year

• Daily Growth: Approximately 0.35 mm (0.014 inches) per day

• Variation by Ethnicity:
  • Asian hair may grow faster, up to about 0.8 inch (2 cm) per month.
  • African descent hair tends to grow slower, around 0.2 inch (5 mm) per month

• Hair Thickness: Thicker hair (>60 μm diameter) grows faster (about 11.4 mm/month) than thinner hair (20–30 μm, about 7.6 mm/month)

• Growth Cycle: Hair growth occurs in phases - anagen (growth phase lasting 3-5 years), catagen (transition), telogen (resting), and exogen (shedding). The anagen phase determines how long hair can grow before it falls out

Additional insights:

• Hair growth rate is largely genetically programmed and remains relatively constant, not significantly influenced by diet, health, or hair care products

• Hair growth slows with age, and individual variation exists even within families

• The perception of slow hair growth often relates to hair shedding before it reaches longer lengths rather than actual growth speed

In summary, hair grows on average about half an inch per month, but this can vary based on individual and ethnic factors, hair thickness, and the natural hair growth cycle.