How long does it take to form a habit?

Does It Really Only Take 21 Days To Form A New Healthy Habit?

The internet is littered with misinformation about health, habits, fitness, and nutrition. If you are trying to adopt a healthier lifestyle and improve your habits, it can be seriously frustrating and overwhelming to try and figure out what is, and isn’t true out there.

So without further ado I would like to introduce a new series on the Adventure Fit For Life blog called “Myths & Mistakes”.

In this series I will address common myths about health, fitness, and nutrition, and discuss how these myths lead to common mistakes that people make when trying to adopt a healthier lifestyle.

So let’s hop right into our first myth!

Fact Or Fiction?

The myth that this post will be investigating is that it only takes 21 days to form a new healthy habit.

What Does The Science Say About How Long It Takes To Form A New Habit?

An important study published in 2009 looked at how long it really takes to form a new healthy habit. A habit is defined as a behavior or action that is repeated often enough to become automatic.

And what does science say about how long it takes to form a new habit?

Drum roll please! 

"It can take anywhere from 18 to 254 days for a person to form a new habit and an average of 66 days for a new behavior to become automatic." ~Gardner et al. from British Journal of General Practice Share on X

Let’s do the math, shall we? 254 days is a little more than 37 weeks, or approximately 9 months.

That’s up to 12 times longer than we were promised by the 21 day habit myth! 

Granted, 254 days is the higher end of the range, and it won’t take that long to form every habit.

The Verdict

I think it’s safe to say that the common belief that a habit takes only 21 days to form is a MYTH.

The truth is that MOST healthy habits take between 2 and 9 months to form.

Where Did The Myth Come From? 

In the 1950’s there was a doctor named Maxwell Maltz. He made the observation that it took his patients at least 21 days to adjust to new situations

For example he observed that a person with an amputated limb would feel “phantom pains” in that limb for roughly 21 days. 

About 10 years later, Dr. Maltz wrote a book that included the following quote: “These, and many other commonly observed phenomena tend to show that it requires a minimum of about 21 days for an old mental image to dissolve and a new one to jell.”

The book, called Psycho-Cybernetics, sold over 30 million copies and many people read it and began to talk about it.

Over the years, Dr. Maltz was misquoted time and again, and the 21 days to a new habit myth was born.

Psycho-Cybernetics, the book that was the source of the 21 days to make a habit myth.

Why Is there So Much Variation In The Amount Of Time It Takes To Form A New Healthy Habit?

The difference between 2 months, and 9 months is huge! What’s that all about?

Honestly, there are a lot of different factors that play into how long it will take for a habit to become automatic. Let’s explore a few of those factors now.

How much time does it actually take to form a new habit? Is it 21 days as the myth suggests?

The Complexity Of The Habit

Some habits are relatively simple, while others are more complicated.

For example, brushing your teeth before work is not an especially complex task – whereas there is a lot more complexity to driving a car.

While both of these actions can definitely become habitual, the simple task of brushing your teeth is almost certain to become automatic before driving a car does.

The Effort Level Required By the Habit

In addition to the complexity of the new habit, the amount of effort that it requires also plays a role in how long it will take to form a habit.

For example, the following healthy habits are relatively low effort:

  • Doing 30 reps of a bodyweight exercise each day.
  • Eating a piece of fruit for lunch each day.

Whereas, these habits demand a relatively high level of effort:

  • Attending a spin class at the gym several times a week.
  • Prepping a whole week’s worth of meals in advance. 

When motivation is low, (which naturally happens from time to time) which habits do you think it will be easier to stick to, and therefore make into a habit?

You guessed it – the habits requiring less effort.

NOTE: You may also notice that the low effort habits are relatively smaller in size than the high effort habits.

This is further support for starting with small habits and building up over time

The Frequency Of The Habit

Frequency of the habit is probably the most important factor when considering how long it takes to form a new habit.

"Habits form based on frequency, not time." -James Clear Share on X

Frequency simply refers to how often you do something. 

The more often you do something, the faster it becomes a habit. Makes sense, right?

So, just as an example, let’s say I wanted to form a habit of working out. And let’s assume that it hypothetically takes performing the habit 100 times (aka 100 workouts) to form this habit.

You could go about getting your 100 workouts in a couple ways.

First, you could choose to work out a little bit each day, every day of the week. That means it would take 100 days (just over 14 weeks) to form the habit of working out. 

Or, alternatively, you could decide to do a little bit longer workout only 3 times a week. If you worked out 3 times a week, it would ultimately take you about 233 days (33 weeks) to reach 100 workouts and form a habit of working out. 

So to sum up our hypothetical example – without changing the amount of workouts you perform, it would either take you 100 days, or 233 days, to form the habit of working out. The only difference here is the frequency (how often) you workout.

So the take away messages are:

  • If you want to form a habit in the least amount of time possible, do a little bit every day.
  • Think about forming a habit more in terms of repetitions than time. 
People ask "How long does it take to form a habit?" but the better question is "How many repetitions does it take to form a habit?" From Atomic Habits by James Clear Share on X

Other Factors Affecting Habit Formation

There are a number of other factors that can affect how long it takes to form a habit, such as personal differences, whether the habit is addictive, and how supportive the environment is etc. But that’s a conversation for another post.

How Believing The Myth Of The 21 Day Habit Sets You Up For Failure

The problem with believing the 21 days to form a new habit myth is that it gives people unrealistic expectations. 

21 days is 3 weeks. That doesn’t seem so bad, right? You can tough it out for 3 weeks no problem!

But say you’re working hard and those three weeks pass and you’re still struggling with your new habit. How would that make you feel if you really believed a habit could be formed in only 21 days? 

You’d probably feel like a failure and wonder what’s wrong with you. You’d likely be discouraged and lose confidence. You might even give up on your new habit or at least really, really want to.

But what if you were given more realistic expectations about how long it will take to form a new healthy habit?

Knowing you were in for the long haul,  you’d likely be a little more patient. If you hit 21 days and still hadn’t completely formed your habit – you’d know that there’s no need to panic, because you know it takes time!

So instead of quitting you keep working hard and are and you’re more likely to successfully form that new habit.


So that’s it, now you know. It takes roughly 2-9 months to form a new healthy habit. 

Let’s put the nail in the coffin on the 21 day habit myth so it doesn’t give anyone else false expectations.

As a recap, you’re in it for the long haul. So to form a new healthy habit:

  • Don’t panic if you don’t see results right away.
  • Be patient (I know, I know – easier said than done, right?).
  • Work on your habit every day if you can.
  • Put in your reps. Practice makes habit.

And maybe most importantly, get started now so that in 2-9 months, your new habit will be automatic, making your day to day life much easier!

Finally, if you liked this post and would like to see more of these MythBuster-style posts, please sign up for the newsletter below!

This is just the first post in what will be a new weekly series – so look out for Myths and Mistakes on Mondays right here on the blog!


Share the knowledge!

Author: clarissa.cabbage

Clarissa is a health coach, autoimmune warrior, and avid adventurer. And she is on a mission to help women escape the diet-culture mentality so they can build healthy habits they actually WANT to stick to - without all the guilt, deprivation and FOMO! When she's not coaching amazing women like yourself, you'll find her outside - hiking, paddling, and hunting for hidden waterfalls on the island of Kauai where she lives with her partner and furry side-kick, Ipo!

39 Replies to “Does It Really Only Take 21 Days To Form A New Healthy Habit?

  1. I really, really enjoyed this post. I’ve struggled with forming long lasting habits, especially when it comes to fitness, for so long. I have a bunch of things I’d like to tackle, like being more regular with my exercise and eating better consistently.

    Right now, I am on Day 67 of not having cola (it was an addiction for me – I used to have it every single day), and I can’t quite say I have beaten the urge for it. But hoping to extend the streak for it as long as I possibly can!

    Really enjoyed the post. 🙂

    1. I’m so glad you enjoyed it Shirsha! I think setting realistic expectations for the timeline of forming habits is so important to being able to stick to them.

      Congrats on 67 days with no cola (or as I would say, pop)!😁 Things that are actually addictive like caffeine can definitely make it take longer to beat the habit due to the dopamine release, but it sounds like you’re well on your way. Keep up the good work, and thanks so much for sharing your experiences! ❤️

  2. Ive always wondered if the whole 21 days thing was true and always thought it sounded a little too good to be true. It’s so hard for me to maintain new habits and I want to get better at it over time.

    Juliana /onlytrulyjuli.wordpress.com

    1. It does sound a little too good to be true doesn’t it Juliana? With myths like this, it’s no wonder most people give up on their goals before achieving them. I think the first step is setting realistic expectations so that you don’t get discouraged. Thank you for reading, and best of luck with your new habits!

  3. Wonderful post ! It’s very difficult to build a new habit. I am almost a failure to build up a regular exercise routine. Let me try again.

    1. Thank you Sankhamala! In my opinion, the only way to fail, is to give up and quit. It’s okay to make mistakes so long as you learn from them and pick yourself back up and try again. We’re only human after all!

  4. It’s good to know that it can take more than 21 days to form a habit. I have previously tried to form a habit of meditating, but now I know I probably just didn’t stick with it long enough! Thanks for the well-written post!

    1. You are very welcome Nicole! I think your example of trying to form a meditation habit is a PERFECT example of the dangers of the 21 day habit myth. Thank you so much for taking the time to comment and add to the discussion.

    1. I am glad you found the tips useful Francesca! Self-reflection is incredibly important for a lot of reasons – but is especially useful to figure out where things went wrong so that we can learn from our mistakes and succeed the next time around! Thank you for reading, and best of luck with your habits.

  5. 254 days?! Eek! That’s a little different than 21! I feel like that’s so important to know, though, because of how discouraging it can be when 21 days passes and you’re still struggling with the habit. Last month I set a 30 day goal for myself to do 100 sit ups a day. I figured by 30 days that would ingrain the habit. Now I know that’s not scientifically true lol! But, since it was one of those easier goals that I did frequently, the habit actually stuck 🙂

    1. Big difference right Alison?! I agree that it’s really important to set proper expectations for yourself for exactly the reason you listed!

      I also think it’s important to note that there is a lot of variation. 18-254 days is a HUGE difference. Not all habits will take 254 days to form. Your 100 sit-ups a day goal is a fantastic example! 30 days could definitely be enough to cement this habit because, like you mentioned – it’s not super complex (sit up, lay down, repeat) and you did it with a high frequency (every single day)! It’s also something you can do at home – that tends to help as well.

      Thank you so much for sharing your experiences about habit formation! 🙂

  6. These are great points and important to blog about. People put a lot of pressure on themselves and get overwhelmed looking at tips from “influencers” and its nice to keep it real!

    1. Thank you Abigail! I 100% agree that “keeping it real” is the best way to succeed. If you believe the myth, it’s easy to feel bad about yourself and start thinking that you aren’t even capable of achieving your new habit.

      Comparing yourself to others (like influencers on social media) is also a sure-fire way to get discouraged. I like to focus on comparing where I am right now, to where I was in the past. This helps to build confidence and therefore makes it more likely that you will actually achieve your habit!

  7. Thank you for sharing this! While mentoring business owners, I’ve found that many are upset that their 21 day sprint to incorporate a new habit in their business falls short of expectations. I’m going to have to start sharing this to help them see why that isn’t necessarily the most realistic expectation. Afterall, we are most successful when our timelines and goals are reasonable. Right?

    1. You’re welcome Britt! And yes, I agree – unrealistic expectations set us up for disappointment at best, and failure at worst. I’d rather know I’m in for the long haul going in so I can plan accordingly!

    1. You’re very welcome! And yes, it’s no easy thing to build a new fitness habit. I think some find the news of the longer timeline to form a habit as being discouraging – but to me, I feel like it’s the opposite. Then we know it’s not a problem with us – that it really is actually hard! And then knowing that, we can prepare ourselves better. Thank you for reading and best of luck with your new fitness goal – keep at it! 💪🏼

    1. Thank you Lisa! I am very excited to start tackling some on those common and annoying health and wellness myths out there. My hope is that it well help people to set more realistic expectations for their goals so that they can plan accordingly and be successful. Thanks for stopping by and checking out my new “Myths & Mistakes” series!

  8. Fantastic points Arcana! I think so long as the thought process is “it’ll get easier after this” instead of, “well, it’s been 21 days so I guess I’m done!” then this is okay.

    It is true that the first weeks are the hardest! However, once we’re past the toughest part, we still have to be vigilant and continue nurturing and working on our new habit which is only partially formed by 21 days (in the vast majority of cases).

    Thank you so much for checking out the first post of my “Myths and Mistakes” series, and for adding to our conversation! ❤️

    1. No judgement Nathalie! I think a lot of people do. It’s a myth that’s been circulating for 60 years! We’ve been told it again and again and even though I think most people’s experiences don’t line up with the 21 day myth, we tend to believe the things we repeatedly hear.

      Thank you so much for reading Nathalie! I hope to be busting a lot more common health and fitness myths, so stay tuned!

  9. Wow this is very eye opening! I was always taught 21 days but it makes more sense that I can take longer for a new habit.

    1. I’m glad you found it informative Lexi! Thanks so much for stopping by and giving it a read. I hope this will help people set more realistic expectations for themselves so they don’t get frustrated and quit when a new habit still feels hard at 21 days.

  10. It is interesting to see how a new habit can be formed within 21 days. It takes a while before your brain recognizes it as a regular thing you do. Not everyone is the same, so some people taking up to 254 days makes sense too. Instant gratification is something a lot of people want but we need to be mindful that if it was that easy, everyone would be doing it. A good mindset to have is, to keep doing it and don’t think too hard. Thanks for sharing!

    Nancy ✨ exquisitely.me

    1. I agree Nancy – everyone wants instant gratification. And if it really only took 3 weeks to form a healthy habits everyone would have them! I like your idea about just keep doing it – I think that this becomes easier when you have realistic expectations about how long it will take. Thanks so much for reading and sharing your thoughts with us! ❤️

  11. Very nice post! I really believe, that our habits are controlled only by willpower because also after 9 months you can stop going to fitness and find 99 reasons why… but with a willpower, person can reach so much more (even without counting days)! I know many persons who told me ”I will do it 21 days and then it will go further automatically”. No, it will not! So, thank you for breaking this belief! 😉

    1. You’re welcome Sandra! I absolutely agree that good habits can be broken at any time if we don’t invest the effort to maintain them. Yes, it becomes easier to do a habit we’ve had a long time, but if we don’t work to maintain it, it can go off the rails as you said. Humans, and all animals, are naturally inclined to take the path of least resistance – to do things that are easy, to conserve energy. So if we want to do big things, we’ve got to be vigilant always that we don’t slip into our old habits. Thanks so much for stopping by to read and adding your insight to the conversation! 🙏❤️

  12. First off, BRAVO for finding the source of the 21-day-to-a-habit myth. I’ve never believed it fully. I always thought it was possible for certain types of habits. But others would require more time, especially like working out or even dieting. I know plenty examples where someone can repeat some healthy initiative for a month, but afterward they fall off because it still hasn’t stuck as a habit.

    1. Thank you Miche Anni! I actually didn’t know the origin of the myth until I started researching it for this article. It’s so funny how the words were over-simplified, kind of like a game of telephone over the years, isn’t it?

      Thanks so much for reading and sharing your experiences with us!

    1. I hope it does Melissa! You’d be surprised how much accurate expectations will change your mindset and therefore how you approach forming a new habit. Best of luck with your goals and please feel free to reach out if you ever have any questions!

  13. This is such an important message. Healthy habits take time and effort. Congrats on your healthy changes and thank you so much for sharing!

  14. Thank you so much for this post! I often felt frustrated at not being able to form a habit after 21 days. Turns out I was misinformed. Now that I know the truth, forming healthy habits will be less frustrating and more successful.

    1. You’re very welcome Tiffany!

      I think the intention was good with the 21-day myth. They wanted to encourage people that they could change their lives by forming new healthier habits, that it wasn’t some far off unattainable thing.

      But I think it really backfired. Just as you said – when people decided to try to build a new habit thinking it’d only take 3 weeks, they’d become so frustrated when they hadn’t formed it after the 3 weeks, and just quit, thinking something was wrong with them. Then they’d never want to try again, especially after several failures at this.

      I think it’s always better to go in with realistic expectations. To tell people, “Yes it’s hard, yes it takes time, but you can do it!”

      Thank you so much for reading, and sharing you personal experiences with us. I hope as you said, this makes forming new habits a little less frustrating!

  15. This was such an interesting read and it definitely gave me a different perspective to this idea of a “21 day forms a habit”. I really enjoyed reading this post x

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