Hair growth calculator
Scalp hair grows about half an inch (1.27 cm) a month — roughly 6 inches a year. This calculator also subtracts your trims, so you get the real timeline, not the fantasy one.
Your hair
Note: trims don't speed up growth — but they stop split ends travelling up, so you keep more of what you grow.
How this works
We start from the average scalp growth rate of 1.27 cm (0.5 in) per month, then subtract the length your trim schedule removes. If you take half an inch off every 12 weeks, that's about 0.17 inches a month gone — so your net gain is roughly 0.33 inches a month, not 0.5.
The faster/slower range uses 1.0–1.8 cm a month, which covers most people. If your trims remove as much as you grow, the calculator will tell you plainly that you won't gain length on that schedule.
Frequently asked questions
How fast does hair grow?
Scalp hair grows about 1.27 cm (half an inch) per month, which works out to roughly 15 cm (6 inches) a year. Most people fall between 1 cm and 1.8 cm per month depending on genetics, age and overall health.
How long does it take to grow hair 6 inches?
At the average rate of half an inch per month, 6 inches takes about 12 months — but only if you are not trimming. Regular trims subtract from your net length, which this calculator accounts for.
Do trims make your hair grow faster?
No. Trims do not speed up growth at the scalp, because growth happens at the follicle. Trims remove split ends so hair breaks less, which helps you keep the length you grow — but every trim still subtracts length.
Why does my hair seem to stop growing?
Usually it is breakage, not growth, that stalls. If your ends snap off at roughly the same rate your hair grows, length appears stuck. Gentler handling, less heat, and lighter trims usually fix this.
Educational only, not medical advice. Sudden shedding or thinning is worth discussing with a doctor. Read our disclaimer.