Project how long your hair will grow. This free hair growth calculator estimates length over time or time to a target length, in cm or inches, using slow, average or fast growth rates.
Hair growth
cm
cm
months
cm
Scalp hair grows about 1–1.5 cm (roughly half an inch) a month on average. Add your current length to project total length or to see how long it’ll take to reach a target.
Length grown
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Enter the details
Growth
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Total length
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Per month
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Per year
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Hair grows from the follicle at a fairly steady rate during its growing (anagen) phase. Genetics, age, health, nutrition and hormones all affect speed — these are averages, and trims don’t change how fast hair grows.
Use this free hair growth calculator to estimate how long your hair will grow over time, or how long it’ll take to reach a target length, based on a typical growth rate.
What this hair growth calculator does
A hair growth calculator projects length using an average growth rate. Enter your current length and a time to see total length, or set a target to see how many months it will take.
How fast does hair grow?
growth = rate per month × months
time to target = (target − current length) ÷ rate
Scalp hair grows about 1.25 cm (½ inch) a month on average — roughly 15 cm (6 inches) a year. So growing from 10 cm to 30 cm takes about 16 months.
Typical growth rates
Rate
Per month
Per year
Slow
~1.0 cm (0.4 in)
~12 cm (4.8 in)
Average
~1.25 cm (0.5 in)
~15 cm (6 in)
Fast
~1.5 cm (0.6 in)
~18 cm (7.2 in)
What affects hair growth
Genetics, age, hormones, nutrition and overall health all influence growth rate. Hair also cycles through growing, resting and shedding phases, so not every strand grows at once — and trimming the ends doesn’t change how fast it grows from the root.
How to use the hair growth calculator
Choose a mode — length after time, or time to a length.
Pick cm or inches and a growth rate.
Add your current length and read the projection.
Hair Growth FAQ
How fast does hair grow?
On average about 1.25 cm (half an inch) a month, or roughly 15 cm (6 inches) a year. Rates vary from person to person.
How long will it take to grow my hair?
Divide the length you want to gain by the monthly rate. To go from 10 cm to 30 cm at an average rate takes about 16 months.
Does cutting hair make it grow faster?
No. Trimming the ends keeps hair healthy and prevents breakage, but growth happens at the root and isn't sped up by cutting.
What affects how fast hair grows?
Genetics, age, hormones, nutrition and overall health. Hair also cycles through growing and resting phases, so not all strands grow at once.
Why is my hair growth slow?
It may simply be your natural rate, but stress, poor nutrition, illness or certain conditions can slow it. See a doctor or dermatologist if you're worried.
Is the hair growth calculator free?
Yes, this hair growth calculator is completely free, needs no sign-up, and gives instant results in your browser.
