The hair growth calculator estimates how long it will take to grow your hair from its current length to your target length. Average growth is 0.5 inches (1.25 cm) per month, but hair type, health, and trimming habits affect the timeline. Enter your measurements in inches or centimeters to get a personalized estimate.
Hair Growth Calculator
Average is 0.5 in (1.25 cm) per month. Adjust if you know your personal rate.
How to Use the Hair Growth Calculator
Growing hair to a target length requires patience and a realistic timeline. The hair growth calculator gives you a month-by-month estimate based on your starting length, goal, hair type, and trimming frequency so you know what to expect.
Step 1: Enter Your Current Length
Measure your hair from the scalp to the tips in inches or centimeters. For curly and coily hair, measure when stretched or wet to get the true length rather than the shrunken appearance. This is your starting point for the calculation.
Step 2: Set Your Target Length
Enter the length you want to reach. Common reference points: ear-length is about 3-4 inches, shoulder-length is 12-14 inches, collarbone is 14-16 inches, mid-back is 24-26 inches, and waist-length is 30-32 inches for most people.
Step 3: Select Hair Type
Hair type affects how much shrinkage you experience. Coily hair (Type 4) can shrink 40-60% from its stretched length, meaning 10 inches of actual growth may only add 4-6 visible inches. The calculator accounts for shrinkage so your timeline reflects what you will actually see in the mirror.
Step 4: Adjust Growth Rate
The default is 0.5 inches per month, which is the scientific average. If you have measured your growth rate before, enter your personal rate. Genetics play the largest role — some people naturally grow 0.3 inches per month, others grow 0.7 inches or more.
Step 5: Factor in Trims
Regular trims prevent split ends from traveling up the shaft and causing breakage. Choose your typical trim frequency. The calculator reduces your net monthly gain by the trim amount divided by weeks between trims to give an accurate net growth rate.
Maximizing Hair Growth
While you cannot significantly speed up your follicle's growth rate, you can minimize breakage to maximize net length retention. Protective styles that keep ends tucked away, sleeping on a satin or silk pillowcase, and reducing chemical processing and heat styling are the most effective strategies for visible length gains over time.
FAQ
Is this hair growth calculator free?
Yes, completely free with no signup required. Calculate your hair growth timeline as many times as you like.
Is my data safe?
Yes, all calculations run in your browser. No data is sent to any server.
How fast does hair grow on average?
Human hair grows approximately 0.5 inches (1.25 cm) per month on average, or about 6 inches (15 cm) per year. Growth rate varies by genetics, age, health, and hair type.
Does hair type affect growth rate?
Hair type affects the perceived growth rate. Coily and curly hair shrinks significantly when dry, so it appears shorter than its actual length. Wavy hair has moderate shrinkage. Straight hair shows the full grown length. The calculator accounts for shrinkage factor.
How much does trimming affect hair growth?
Trimming does not speed up growth — hair grows from the follicle, not the ends. However, regular trims prevent split ends from traveling up the shaft and causing breakage, which can reduce your net length gain. A 1/4-inch trim every 8-12 weeks is a common balance.
Can I grow hair faster than 0.5 inches per month?
Some people naturally grow hair at 0.6-0.8 inches per month. Diet, scalp health, reduced breakage, and supplements like biotin may help you reach your natural maximum, but cannot exceed your genetic ceiling.