How fast does hair grow on average?

Scalp hair grows approximately 0.5 inches (1.27 cm) per month, or about 6 inches (15 cm) per year. This varies by genetics, age, health, and nutrition.

Why does my hair seem to grow slower than 0.5 inches per month?

Hair loss from breakage, heat damage, or split ends can offset growth, making net length gains appear smaller. Regular trims to remove damaged ends and protective styling can help retain length.

Does hair grow faster in summer?

Some studies suggest hair may grow slightly faster in warmer months due to increased circulation, but the difference is small — usually a fraction of a millimeter per month.

Can supplements make hair grow faster?

Biotin, collagen, and other supplements may help if you have a deficiency, but evidence for significantly accelerating growth in healthy individuals is limited. Consult a dermatologist for personalized advice.

Does the calculator account for trims?

No. Trims remove length. If you plan regular trims, add that trim length to the gap between current and target lengths, or extend your timeline accordingly.

How accurate is this calculator?

It is a planning estimate based on average or self-reported growth rates. Actual results vary by individual. Use it to set a realistic goal, not a medical prediction.

Hair Growth Calculator

Name: Hair Growth Calculator
Availability: InStock
Author: Nham Vu

Enter your current hair length and target length to see how many months it will take to reach your goal.

Your Hair Details

Current hair length (inches)

Target hair length (inches)

Monthly growth rate (in/month)

Average is 0.5 in/month (1.27 cm/month). Leave blank to use the default.

Fill in your details and click Calculate to see your hair growth timeline.

Summary

Enter your current hair length and target length to see how many months it will take to reach your goal.

How it works

Enter your current hair length in inches or centimeters.
Enter your target (desired) hair length.
Optionally adjust the monthly growth rate if you know yours differs from the average.
Click Calculate to see your estimated time and a month-by-month milestone chart.
Use the results to plan growth check-ins, trims, and styling goals.

Use cases

Plan how many months you need to grow hair for a wedding or event hairstyle.
Track progress toward a long-hair goal after a short cut.
Estimate recovery time after a haircut that was shorter than intended.
Set realistic expectations when growing out a pixie cut or bob.
Compare growth timelines at different monthly rates (e.g., with supplements).
Plan when to schedule trims without losing progress.

Frequently Asked Questions

Related tools

Hair Dye Mixing Ratio Skincare Routine Order Spf Reapplication Timer

Last updated: 2026-05-29 · Reviewed by Nham Vu