The rate at which hair grows depends on many factors, including the person’s age, race and diet.
Healthy human hair grows at an average rate of 0.01 inch (0.35 millimeters) per day, which adds up to roughly 0.5 inch (13 mm) per month, or 6 inches (15 centimeters) per year, according to the medical resource StatPearls
Read more: https://www.livescience.com/42868-how-fast-does-hair-grow.html
