How fast does hair grow?

Hair growth rates can vary significantly from person to person, but on average, hair grows about half an inch per month, which equates to roughly 6 inches per year. This general guideline is based on typical growth patterns, taking into account factors such as genetics, health, and age.

The other choices suggest higher growth rates that are not reflective of average hair growth. For instance, 12 inches per year would imply hair growing at a rate of 1 inch per month, which is above the typical average. Similarly, while 1 inch per month and 3 inches per year might be true for some individuals with particularly fast-growing hair, they are not the average rates observed in the general population. Thus, understanding that 6 inches per year represents the common growth rate helps clarify why this answer is the most accurate.