Hair Growth Calculator: How Fast Does Hair Grow?

Hair Growth Calculator

Hair Growth Calculator

Enter the number of months for which you want to calculate hair growth. This period could be based on a specific goal, like a target date for an event or just how long you're willing to wait to see your desired results.

Hair grows on average ½ inches per month, so we've set the default value for this field. We don't recommend changing this value unless you're sure that your hair grows faster or slower than the average.

This field is optional. If you know the current length of your hair, you can input it here to calculate your overall hair length after the projected growth. This will be the sum of your current hair length plus the expected growth. If you prefer not to include your current hair length in the calculation, simply leave this field blank.

The calculator will display your estimated final hair length in inches. This figure is derived by adding together your current hair length and the estimated new hair growth over the input number of months. Please note, this is an estimation and individual results may vary based on various factors like health, diet, hair care routines, and so on.

Interested in knowing how long your hair will be at defined points in time? Estimating future hair length can be tricky, but coming up with an educated prediction is 100% possible. Whether you’re serious about growing your hair to a certain length or are just curious about your hair growth potential, this is where you need to be.

On this page, you’ll find a hair growth calculator, which is an online tool that provides you with an estimate of your hair length after a given period of time using a hair growth formula. In addition to that, we’ll provide research-based information about hair growth stages and factors that influence your average hair growth rate.

Get to Know the Hair Growth Cycle

Your hair is always growing…or at least a portion of it is. Every hair on your head is subject to the growth cycle, where it grows, transitions, rests, and then sheds, ending up in your shower drain and styling tools.

At any given time, about 85 – 95 percent of your hair follicles are in the growing stage, and the rest is in one of the other phases. Below, we’ll discuss the stages of the hair growth cycle:

Note: Some experts only recognize three distinct hair growth phases, while others acknowledge four. We’ll focus on all four.

A young Hispanic female with long hair has a below average rate of slower hair growth due to the lack of essential nutrients from a high-quality diet.

The Anagen Phase – Growing Phase

This phase is the active growth phase for hair follicles, lasting anywhere from two to seven years. The Anagen phase is determined by genetics and can vary from person to person. During this stage, hair grows about a half inch per month.

The Catagen Phase – Transition Phase

Also known as the transitional phase, the catagen phase usually lasts only two or three weeks. It is the brief transition period between growth and rest. During the catagen phase, hair growth slows or stops, and the hair’s root detaches from the bottom of the hair follicle. Experts estimate that about 5 percent of hair is in this stage at any moment.

The Telogen Phase – Resting Phase

During the telogen phase, the hair still isn’t growing. It is resting. About 10 – 15 percent of your hair is in this stage at any moment. The telogen phase is roughly three months long.

The Exogen Phase – Shedding Phase

After the resting phase is the shedding phase – the exogen phase. In this phase, old hair falls out, and new hair starts to grow in the follicles. The hairs don’t pop out spontaneously; your hair care and styling routines encourage this shedding to occur. The exogen phase for any individual hair could last up to 5 months.

Despite her below-average rate of hair growth, she takes steps to nourish her hair and promote healthier growth.

How Fast Does Hair Grow?

Now that you know more about the hair growth cycle and its stages, let’s get to the question you’re likely most interested in – how fast does hair grow? On average, healthy hair grows about half an inch per month, or 6 inches a year.

Though, there will be some variation between individuals based on several factors:

What You Eat

A healthy diet is essential for hair growth. Foods rich in Vitamin C, Biotin, Iron, Zinc, and vitamin E can promote healthy hair growth. And if you’re deficient in any nutrients vital to hair growth, your hair growth could stall or stop for a time.

If you’re not sure whether you have a vitamin deficiency, it’s best to speak with your healthcare provider. They will run any necessary tests to determine which supplements and vitamins, if any, you might need.

Hair sheds and regenerates in a continuous cycle, and her hair length depends on the rate of growth and shedding.


Your hair growth rate also slows down as you age. Generally, people from ages 15 to 30 see the fastest hair growth rate compared to other age groups. Hair tends to grow slower past age 30 and even slower still for older individuals.

Your Genetic Makeup

Your genetic makeup also affects your hair growth rate. Some people are genetically predisposed to faster-growing, longer hair than others. Other people’s hair may take longer to reach certain lengths. But, despite gene variation, hair growth rates are still pretty consistent.

Whether You Retain Your Length with Mindful Hair Care

The amount of hair growth you see on a regular basis is directly affected by your hair care routine. Do you frequently color or bleach your hair? Do you heat style your hair without using a heat protectant? If so, you might be damaging your hair, making it harder to retain length.

If she experiences excessive hair loss, it may affect the overall length and thickness of her hair.

How to Calculate Hair Growth

Calculating hair growth is much simpler than it seems. All you need to know is how many months you’d like to calculate growth for.

Hair Growth Calculator Formula

Since we know that, on average, hair grows about a half inch per month, you can multiply 0.5 inches (or ½ inches) by the number of months you plan to track hair growth.

For example, if you wanted to know how much hair you’d grow in 2 months, you would multiply 0.5 inches by 2 and get 1 inch. This means that your hair would grow 1 inch in 2 months. You can do this same calculation for 10 or 20 months to get an idea of how much hair you can expect to grow over that time period.

Of course, the results of any hair growth calculator won’t be 100 percent accurate – many factors can affect the rate at which your hair grows. Although, it’s a great way to satisfy your curiosity about how much hair you can expect to grow in a certain amount of time.

Growing hair is a gradual process, and she patiently waits for her hair to reach the desired length.

What to Do with the Information from This Calculator

After you get your results from the hair growth calculator, you might not know how to use the information. If this resonates with you, keep on reading. While it’s great to know that your hair can grow so much in a certain amount of time, there are some things you can do to keep your hair healthy and ensure that it reaches its full potential.

If you are underwhelmed by your results, that’s understandable.

Just know that superhuman hair growth rates are not the norm, and it takes time to get to the length you may be dreaming of. You’ll find loads of products online that claim to speed up your hair growth, but the vast majority of them will do nothing more than empty your bank account.

To ensure that you reach your hair length goals, it’s essential to practice proper hair care, including using the right products for your hair type and avoiding excessive heat tool use (and using a heat protectant when necessary).

Additionally, trim your hair regularly to keep split ends and other damage at bay. It also helps not to go overboard with chemical treatments like relaxers, perms, hair coloring treatments, and the like.

Finally, ensure you are getting the essential vitamins and minerals needed for optimal hair growth, such as biotin and vitamin E. You can get these through your diet and/or via supplement form.

And if you ever have questions, don’t hesitate to ask a hairstylist in your area or do some research on it yourself. Sometimes, it’s best to get professional help to maintain your hair’s health. There are some things that you just don’t know.

Can Hair Grow 2 Inches in a Month?

While we would all love to be healthy hair gurus and see our hair grow 2 inches in a single month, unfortunately, this is typically not the case. The average hair growth rate is about half an inch per month. Factors such as genetics, diet, and hair care practices can influence this rate, but a net growth of 2 inches in a month is highly unlikely. It’s essential to remember that your hair’s health is more important than rapid growth, and maintaining a balanced diet and proper hair care routine can prevent significant hair loss.

How Do I Calculate My Hair Growth?

Calculating your hair growth is easier than it seems! Here’s how: We know that hair grows at a rate of approximately half an inch per month. So, if you want to calculate how much hair you’ve grown over a certain period, multiply 0.5 inches by the number of months you’re considering. For example, if you want to calculate the amount of hair grown over six months, multiply 0.5 inches by 6. This calculation gives you a net growth estimate. Remember, this is just an estimate; growth can be influenced by various factors, including hair care routines and genetics.

How Long Does It Take to Grow 1 Inch of Hair?

On average, it takes about two months for your hair to grow 1 inch. This calculation is based on the average hair growth rate of half an inch per month. However, this rate can vary from person to person and can be influenced by factors such as diet, age, and hair care practices. Calculators that consider the stages of the hair growth cycle can provide an estimated date when your hair will reach a desired length.

How Long Does Hair Grow in 2 Weeks?

The length of hair grown in 2 weeks can be calculated using the average hair growth rate. As hair typically grows at about half an inch per month (or approximately 0.125 inches per week), you can expect your hair to grow about 0.25 inches or a quarter of an inch in 2 weeks. Remember, this is an average, and the actual length could be more or less due to age, genetics, and hair care habits. Hair loss due to breakage or poor practices could also affect your net length gain.

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We hope that this hair growth calculator and accompanying tips have been helpful to you and that it has given you valuable insight into the hair growth cycle and factors that affect your hair growth and length retention.

By combining the knowledge provided by this calculator with mindful hair care practices, you can reach the hair length of your dreams. We wish you the best of luck with your hair care journey!

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