Hair growth calculator: how long until your hair reaches the length you want
Growing out a cut takes patience, and this hair growth calculator tells you how much. Enter your current length and a goal — shoulder, armpit, mid-back, waist or any number — and it gives the time and the calendar date you should get there, allowing for regular trims. A chart shows the length month by month, and a table lists when you pass each landmark on the way.
It starts from the average rate dermatology sources quote, about ½ inch (1.27 cm) a month, but rates differ a lot between people. Switch to My growth rate to measure yours from two dated measurements, then plan with your own number. It works for men and women alike — the rate does not depend on the haircut.
How to use the Hair Growth Calculator
- Choose inches or centimetres and type your Current length, measured from the scalp to the ends.
- Pick a Goal or type a target length.
- Keep the average growth rate, choose another preset, or type your own.
- Enter how much your stylist trims and how often (0 weeks if you don’t trim).
- Read the time and date, the chart and the landmark table; copy the plan to your notes.
- Optional: in My growth rate, enter two measurements a few months apart and press Use this rate.
Hair Growth Calculator features
Trims included
Each trim takes length off on a schedule, so the answer is the real date, not just length ÷ rate.
Date and duration
The answer as “about 2 years” and as a calendar date from any starting day.
Landmark table
Ear, chin, shoulder, armpit, mid-back, waist, hip and tailbone lengths with the time to each.
Growth rate calculator
Measure your own growth per month from two dated measurements, allowing for any trim in between.
Growth chart
A month-by-month line of your length with the trims as small steps down and the target marked.
How fast does hair grow?
MedlinePlus, the US National Library of Medicine’s health site, says it takes about a month for healthy hair to grow half an inch — about 6 inches (15 cm) a year. A 2020 review of Asian hair in Clinical, Cosmetic and Investigational Dermatology lists measured averages of 411 µm a day for Asian hair, 367 for Caucasian and 280 for African hair, which is about 1.25, 1.12 and 0.85 cm a month. Individual rates vary with genetics, age and health, which is why measuring your own is worthwhile.
Each hair grows only during its growth (anagen) phase, which DermNet says lasts up to six years or longer on the scalp. At ½ inch a month, six years is about 36 inches, so very long goals are not reachable for everyone.
How the calculation works
Without trims the time is simply (target − current) ÷ rate. With trims, the calculator steps through each trim interval: between trims the hair grows at the full rate, and at each trim it loses the trimmed amount. It finds the first moment the length reaches the target. If a trim removes as much as grows between trims, the target is never reached, and the page says so.
Worked example: from 6 in to armpit length (16 in) at ½ in a month, trimming ¼ in every 12 weeks, takes 731 days — about 2 years — instead of 20 months without trims: the eight trims on the way cost 2 in.
| Goal (from the scalp) | From 6 in, no trims | With ¼ in every 12 weeks |
|---|---|---|
| Shoulder, 11 in | 10 months | 1 year |
| Armpit, 16 in | 1 year 8 months | 2 years |
| Mid-back, 18 in | 2 years | 2 years 5 months |
| Waist, 24 in | 3 years | 3 years 7 months |
Measuring your hair
For a countdown to the date, use the date calculator, and to convert lengths try the length converter. Planning an outfit around your new length? The necklace length chart shows where each chain sits. This page is for planning only — if your hair is thinning, shedding a lot or not growing, see a dermatologist.
- Measure from the scalp at the crown or the back of the head to the ends, the same way every time.
- Gently stretch curly or coily hair, which can shrink to half its length or less when dry.
- Measure every month or two on the same strand area; two measurements three or more months apart give a steadier rate.
- Landmark lengths are approximate for straight hair on an average adult. A taller person needs more hair to reach the waist.
Hair Growth Calculator FAQ
How fast does hair grow per month?
On average about ½ inch (1.27 cm) a month, or 6 inches a year, according to MedlinePlus. Some people grow faster or slower; use the growth rate calculator to measure yours.
How long does it take to grow hair to shoulder length?
From a short 2-inch crop to about 11 inches at the shoulder takes roughly 18 months at ½ inch a month, longer with regular trims.
Does the hair growth calculator work for men?
Yes. Men’s and women’s scalp hair grow at similar average rates, so the same calculator works for growing out a crop or a beard-length style on the head.
Do trims make hair grow faster?
No. Hair grows from the follicle, so cutting the ends does not change the rate. Trims remove split ends, but they also take length away, which the calculator accounts for.
How do I calculate my hair growth rate?
Measure the same section of hair on two dates at least a month apart, add anything trimmed in between, and divide the difference by the number of months. The “My growth rate” tab does this for you.
Why has my hair stopped getting longer?
Each hair grows only for its growth phase, which can be a few years. When hairs reach the end of it they rest and shed, so everyone has a natural maximum length.