Hair Growth Calculator
Estimate how long hair takes to grow.
Average ~0.5 in (1.25 cm)
Results update as you type.
How it works
Growing hair to a desired length takes patience, and this calculator estimates how long it will take. You enter your current hair length, your target length, and your monthly growth rate, and it returns the time in months and years. The calculation divides the length you need to gain by your monthly growth rate. Scalp hair grows about half an inch (roughly 1.25 centimeters) per month on average, or about six inches a year, though this varies by individual, age, genetics, health, and hair type — some people grow faster, some slower. So going from a 6-inch bob to 12-inch long hair at the average rate takes about 12 months. Growth rate is largely determined by genetics and cannot be dramatically sped up, but you can support healthy growth and minimize breakage (which makes hair seem to grow slower) through good nutrition, gentle handling, regular trims to prevent split ends from traveling up the strand, and managing stress. Note that visible length also depends on breakage and hair health, not just growth from the root, so protecting the ends helps you retain length. Marketing claims about products that dramatically accelerate growth are generally unfounded. Use your own observed growth rate if you know it for a more personal estimate. Enter your current and target length and growth rate to estimate the time.
Months = (target length − current length) ÷ growth per month
The time to reach your target hair length is the difference between the target and current length divided by the monthly growth rate. With the average scalp hair growing about half an inch per month, longer goals naturally take proportionally more time.
Source:Average hair growth rate
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter current hair length and target hair length.
- 2
Adjust the options
Adjust growth per month if they apply — sensible defaults are already set.
- 3
Read your result
Time to reach goal updates instantly as you type — no button to press.
Frequently asked questions
How long does it take to grow hair?
Divide the length you want to gain by your monthly growth rate. At the average of about half an inch per month, gaining 6 inches takes roughly 12 months. Growth varies by person, so someone growing faster or slower than average will differ. Use your own rate if known for a more accurate estimate.
How fast does hair grow on average?
Scalp hair grows about half an inch (roughly 1.25 centimeters) per month, or about six inches a year, on average. Individual rates vary with genetics, age, health, hormones, and hair type. Body hair grows more slowly. This calculator uses half an inch per month by default, which you can adjust to your own observed rate.
Can I make my hair grow faster?
Growth rate is mostly genetic and cannot be dramatically increased, despite many product claims. However, you can support healthy growth and, importantly, reduce breakage so you retain more length. Good nutrition, gentle handling, avoiding excessive heat and tight styles, regular trims, and managing stress all help hair grow to its potential and stay healthy.
Why does my hair seem to stop growing?
Hair rarely stops growing from the root, but breakage at the ends can offset new growth so length seems stuck. Damage from heat, chemicals, or rough handling causes split ends and breakage. Protecting the ends with trims, gentle care, and moisture helps you retain the length your hair is actually growing, so it visibly gets longer.
Do hair growth supplements work?
For most people with a normal diet, supplements provide little benefit beyond correcting an actual deficiency. If you lack nutrients important for hair, like iron, protein, or certain vitamins, addressing that can help. But for those already well-nourished, supplements rarely accelerate growth meaningfully. A balanced diet and healthy hair habits matter more than most marketed products.