On average, hair grows about half an inch (1.25 cm) per month or about six inches (15 cm) per year. However, the rate of hair growth can vary depending on several factors such as genetics, age, health, and nutrition. Additionally, different parts of the body can have different rates of hair growth, and some people may experience faster or slower hair growth than others. Factors that can affect hair growth rate include: Age: Hair growth tends to slow down as we age, and older individuals may experience slower hair growth than younger individuals. Gender: Men tend to have faster hair growth than women. Genetics: Hair growth rate can be determined by genetics. Some people have a faster hair growth rate than others due to their genes. Health: Health conditions such as thyroid disorders and nutritional deficiencies can affect hair growth rate. Nutrition: A diet rich in protein, vitamins, and minerals can promote healthy hair growth and prevent hair loss. It's important to note that hair growth rate is just an average, and it can vary from person to person. Some people may experience faster hair growth, while others may experience slower growth. Additionally, factors like hair care practices, stress levels, and medication use can also affect hair growth.