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How Long Does It Take to Form a Habit?



Let’s say that you decide that every night before you go to bed, you’ll walk around your house and clean up anything that’s out of order: you put any last dishes in the dishwasher, pick up any dirty clothes, shelve any books that are lying around, etc., so that in the morning you can wake up to an ordered house, because you find that makes you happier to start the day. You do it for a few days. You’re very proud of yourself. Then you’ve been doing it for a week. Then you’ve been doing it for a month, all without missing a day. Is that enough for it to be a habit? As usual, there’s a short answer and a long answer. The short answer is “probably not.” The long answer follows.

Science to the rescue: some hard numbers
I’m working from a single study, “How are habits formed: Modelling habit formation in the real world” by Phillippa Lally, Cornelia H. M. van Jaarsveld, Henry W. W. Potts, and Jane Wardle in the European Journal of Social Psychology, so we’re definitely talking about actual science here, but it’s just one study, so take this information as tentative for now. With that said, let’s plunge into the long answer.

The long answer is that there seems to be no set length of time it will take a person to develop a habit. Different people will take different lengths of time, and different habits will also take different lengths of time: for instance, it seems that complicated behaviors take longer to become habits than simple ones.

In the study I link to above, the range of time it took people to form habits (specifically, to “reach 95% of their asymptote of automaticity,” and if you don’t have to look up at least one word to understand that, you did better than I did) ranged from 18 days to 254 days, the average being 66 days. As a general rule of thumb, then, two or three months is often going to be enough time for something that you repeat daily to become a habit. According to the study, missing the habit just once in that time didn’t seem to cause trouble, though more than once did.

That long?
On the one hand, that’s depressing: that’s a long time to have to work that hard at something! On the other hand, this is great: in just two to three months, you can turn many behaviors into habits that you just do automatically without worrying much about them. Cleaning, answering letters in a timely fashion, speaking diplomatically, exercising, eating well–any one of these might well be within your grasp before Christmas. We already knew that habits don’t come automatically; this just gives us a better idea of how much work they take.

A little help from Kaizan
If you’d like a little help with keeping a habit, Kaizan has a good tip for helping habits not break down: How to Make Sure That Nothing Gets Between You and Your Good Habits.

In the comments to that post, someone cites an often-repeated piece of information that it takes 28 days to form a habit. I’ve heard this more than once, but never heard that it was based on any reliable research. My guess is that it’s meant to be inspirational guesswork, and since people like round figures so much, it caught on. I’ve also heard 21 days cited; don’t believe that one either. In any case, the comment drove me to find research that gives something more like a real answer to the question, which led me to Lally, et al.’s study.

Don’t get too attached to a number
We’ll want to try not to get too wrapped up in a specific number of days, like this article, where they seize on that 66-day average and proclaim it as a universal truth. However much we human beings like a simple, unchanging answer, 66 days is just an average: your mileage is extremely likely to vary.

Why it doesn’t always matter
And it may help to act as though habit formation won’t be happening at all, to simply use feedback loops to keep up good practices and make good choices, and to take habit formation as a wonderful accident. As with any other positive development that results from being motivated, habit formation causes problems if it’s thought of as the end goal: it’s essential to find things to enjoy about the steps along the way in order to keep up anything important long enough for it to matter.

Photo by .scarlet.



  1. Charles  •  Sep 14, 2009 @9:45 am

    Very interesting!

    I had read that three weeks was enough for a habit, but that source was obviously not based on any scientific backing.

    It’s nice to know what I’m up against for habit forming, even if the news aren’t good news persay.

    I would love to have that “set the place clean before I sleep” habit. A good goal to work on.

  2. Luc  •  Sep 14, 2009 @10:21 am

    Charles, thanks for the comment. I like that habit, too: for now task and time management are my focus, but down the road I hope to pick that one up myself. It might even be one of those rare ones that can pretty easily be picked up while pursuing some other goal, because you only have to think about it once a day, and it doesn’t require any preparation. I’ll have to experiment with something like that …

  3. Robin Dickinson  •  Sep 15, 2009 @6:38 am

    Hi Luc,

    I always appreciate the rigor with which you approach the subject. I’m a huge fan of habits because they help me to “stack” tasks.

    NOTE: Stacking tasks is my take on multi-tasking i.e. in my experience, you can only multi-task by combining automatic tasks with one non-automatic task e.g. I go running (automatic) and practice a language (non-automatic) = stacking.

    The sooner I can get a desired action to become a habit (in this case I mean something that can be “automated” i.e. implemented without engaging much mental RAM), the sooner I can stack it.

    So, I’m highly motivated to find ways of accelerating habit formation (irrespective of the published data, although I certainly use that as a reference point).

    In your opinion, what role does the level of self-motivation play in the time it takes to form a habit? Has this been researched?

    Perhaps this is something we should discuss one day.

    Sorry to ramble, but your post is thought provoking.

    Best, Robin

  4. Luc  •  Sep 20, 2009 @10:41 pm

    Thanks for posting the comment, Robin, and for the perspective on stacking. I’ve tended to approach that subject from the negative side (that it’s very hard to attend to more than one major goal or project at a time unless all but one have been going on so long that they’re habitual), and while I think that’s a useful warning to keep in mind, tackling the same idea from the positive side (as soon as you make behavior toward a goal into a habit, you can add a new goal) seems likely to be especially encouraging in some situations.

    I’m afraid I haven’t come across research about the effect of level of motivation on how quickly we acquire habits, but from some things I know about the process, I can at least make an educated guess.

    First, I picture greater motivation as always meaning more mental involvement with a task: that is, spending more brain time on it and/or having a strong, positive emotional connection to the goal (as strong emotions tend to reinforce learning very effectively). Spending more mental time on a goal should increase the number of neural connections in the brain that service that goal, which should make the task easier and more natural, although I would guess that performing a specific task for that goal might not be strongly affected by other activity toward the same goal. For instance, if I think about an exercise regime a half dozen times a day but work out once a day, I suspect the speed at which I automatically go work out will be much more based on those actual exercise sessions than on how much I think about it, because the habit of starting the workout would be a specific set of neural connections in my brain rather than a function of any thinking I do about exercise.

    However, if I experience strong positive emotions when I work out, for instance because I’ve recently moved to an area I love and my daily run is the time when I get to go out and see it all, I suspect the habit may form more quickly, because emotion can help us learn more quickly and thoroughly.

    I’ll keep a lookout for hard evidence on the subject one way or another!

  5. Steve  •  Jan 22, 2010 @2:05 pm

    Luc, I thought it was William James who said that a new habit would take 21 days to develop, with continued daily practice. Might be wrong and if not, unsure how he came to this conclusion. Had another question however. My understanding is that we develop neuro pathways that support our habits and that changing a habit is in essence, doing something that is contrary to your brain’s hardwiring. With neuroplasticity the brain can develop alternative routes of internal communication that support new, healthier habits. Question is how long might this process take? I think this is important info for those being treated with cognitive behavioral techinques and for their care providers who give them expectations about the likelihood of succeeding at behavioral change, ie to know wha they’re up against.

  6. Luc Reid  •  Jan 22, 2010 @2:23 pm

    Steve, thanks very much for the comment!

    I see a quote about the 21 days attributed to William James on a weight loss Web site (I don’t want to link to something that I feel may be dubious), but it doesn’t cite the work, and since I can’t find any reference to the same quote anywhere else on the Web, I’m not confident that it’s accurate, particularly since the quote is being used to try to sell a 21-day weight loss program.

    The idea is attributed to Zig Ziglar on another site I saw, which would imply it’s not founded on research but rather personal opinion if that’s the real source.

    James did seem to have some very useful ideas to put out about developing habits, although his advice about them was more generalizations based on observation than conclusions of research, and I think should therefore be considered speculative. I must say that I have a lot of respect for James, however!

    About how long the process takes, off the top of my head it seems to me that the question of how long it takes to rewire a pattern in a human brain and how long it takes to change a habit are the same question. It wouldn’t seem reasonable that the amount of time this would take would be anywhere near the same for all people regarding all habits or thought patterns under all circumstances, which delivers a further swift kick to the “21-day” idea or any other set time length. So the answer seems to be that it may take anything from a bit less than a month to ten months, as long as the new behavior is practiced daily and the person virtually always sticks to the new behavior.

    That’s the trouble, though: very few of us are prepared to keep up behavior contrary to our habits for months at a time without a few lapses, so new habits are very hard to form. Of course, that’s what this site is all about: providing the tools we need to be able to do exactly that.

  7. Annoni  •  Mar 17, 2010 @7:14 am

    Hi, I don’t normally respond to these comment sections so I’m not sure I’m even doing this correctly. This is also my first time visiting this website as well and I just had a minor brainstorm, please don’t think I’m crazy or gone off the deep end because I’m going to quote a Bible Scripture, Matthew 18:21,22 KJV, (21)Then Peter came to Jesus and asked, “Lord, how many times shall I forgive my brother when he sins against me? Up to seven times? (22) Jesus answered,”I tell you, not seven times, but seventy times seven.”– Seventy times seven is fourhundred and ninty times, could that in a rudamentary semiconclusive way be the number of times someone needs to do an action to make it an automatic reaction. They did not have psychologists back in Bible times or even back when the Rosary was brought into use, or prayer beades for that matter. Could what your trying to explain and what I’m trying to understand also be alittle of what early philosaphers were also trying to explain as well? Just an idea, thank you for listening sorry for the run on sentencing 🙂

  8. Luc  •  Mar 17, 2010 @7:31 am

    Well, if we’re talking about a daily habit taking from 18 to 254 days in this sampling, then I think we’re looking at repeating that action a few dozen times to at most a few hundred times before it really sinks in. So as far as I can tell, even a very complex behavior is likely to become habit under the right circumstances long before getting to 490 repetitions.

    Timing is important, too. Doing something ten times in one day and then not again for a week is unlikely to be nearly as successful in forming a habit as doing it once a day for a week, based on the findings in this study, and as also suggested by the rules of memory formation (for instance, as described in John Medina’s book Brain Rules), even though forming habits and forming memories don’t entirely use the same mechanisms.

  9. Annoni  •  Mar 17, 2010 @8:45 am

    Thank you for the information and getting back to me so quickly. And Definately thank you for not saying I was nuts. Have a great day today.

  10. Gabe  •  Jan 5, 2011 @4:10 pm

    According to this site listed below, the original source for 21 days comes from Dr Maxwell Maltz. He noticed that amputees took, on average, 21 days to adjust to the loss of a limb and he argued that people take 21 days to adjust to any major life changes. I have not verified this statement with medical literature, however.

  11. Luc  •  Jan 6, 2011 @10:16 am

    Gabe, thanks for that! I wonder if the 28 day rumor got started in a similar way, or if it was just a misstatement of Maltz’s idea.

  12. Lei Scher  •  Jan 23, 2011 @10:34 pm

    I’m curious about your take on stubbornness as it pertains to a habit. I know of an adult that vowed not to speak to his family because he was angry over something very trivial. He kept his promise. It was at least 13 years before he’d more than whisper to the family he lived with. For the most part, he wrote notes. I assumed there was mental illness when I first met the family. I was assured, he was just stubborn.

    Later in life, this mans brother began doing the same thing. He was angry over something unrelated to his children, but nonetheless, stopped talking to them. It’s been six months now and he won’t speak to them. Ironically, he added them as Facebook friends but wont speak to them.

    Are you aware of any studies that deal with “habits” that alter ways of life?

  13. Luc  •  Jan 24, 2011 @10:55 am

    Hi Lei,

    That’s certainly taking stubbornness to an extreme. Off the top of my head I can’t think of any research to point you to, but I’m digging around to see what I might be able to turn up.

    From the very little I know, I imagine there are broken ideas/cognitive distortions at work, things like “I can’t back down” or “They shouldn’t have done that to me” or “I have to keep doing this.” Certainly it seems to be the case that people can talk themselves into all kinds of very persistent behavior by coming up with counter-productive ways to think of a situation.

    I hope to find something useful about stubbornness; if so, I’ll post and e-mail you about it.

    Best wishes,

  14. Aastha Diwan  •  Nov 18, 2011 @6:07 am

    I am taking sleeping pills in large quantity for last two years.Just want to get rid of it and surprised to know about average period of 66 days,as 21 days appeared to be very easy period .Plz guide.

  15. Luc  •  Nov 18, 2011 @11:17 am

    Hi Aastha,

    Remember that 66 days is only an average, and any particular habit may take more or less time. If I try to change a habit, it will tend to take less time if I can be very consistent about it, if it’s something that comes up often, and/or if it’s something that isn’t very complicated or difficult for me; it will tend to take more time if I have trouble being consistent with the change (which is the hard part, of course!).

    With sleeping pills, though, it sounds as though physical addiction could be a factor, and an addiction is more than just a habit. Habits are behaviors we do without making a conscious choice because we’ve strengthened the paths for those behaviors in our brains. Physical addictions are that plus other chemical and physiological issues, and that can make them much more complicated to deal with. I’d definitely suggest looking for advice from a psychiatrist or physician who knows a lot about getting over physical addictions. Habits are an important part of that equation, but only part.

    Good luck!


  16. Sarasan Sé  •  Jan 19, 2012 @7:41 pm

    Hi Luc,

    It was very nice to read this article, because I am a language teacher, and basically teaching a new language to a beginner is very much about introducing a set of new habits in a person, the course I am running is for just 40-50 days. Not 66 days, and moreover each day is not exactly a repetition of the previous one.

    Well is there anything that you know in habit psychology that could help me design my language lesson plan content in a better way.


  17. Luc  •  Jan 19, 2012 @9:33 pm

    Hi Sarasan,

    Thanks for commenting. Your parallel between learning a language and picking up a new habit makes a lot of sense to me.

    About planning lessons, there are a few posts I have on that site that might be of interest:

    Learn It Again, Sam
    Book Review: Brain Rules
    Improving Motivation Through Better Memory and Learning

    Let me know whether or not these prove useful! I think the material from Brain Rules, which supplies some information to all three posts, is especially useful when talking about learning.


  18. djay  •  Feb 15, 2012 @12:30 am

    In December 2010, I decided that I needed to brush my teeth every night before bed no matter how late or how exhausted I was. Sound simple? Well, yes and no. 16 months later, I have managed this every night except 2. Yet, in spite of the length of time that this has been in place, I still find that I have to think about it every night. The habit is not automatic like it is in the morning when I wake up, walk into the bathroom, take care of whatever, including brushing my teeth without thought. So I still want to know how long it takes to form a habit that takes place automatically without a deliberate decision each time.

  19. Luc  •  Feb 15, 2012 @9:51 am

    That’s a very interesting example, djay. I don’t think there’s a direct answer to the question of how long it will take, but I do have a couple of questions: do you brush your teeth at the same time every night? Are there any changes in how, when, or where you do it? Habits form most easily when you do them the same way every time and at the same prompt. If you’re doing things in the same place and in the same way every night, I’d definitely like to talk to you more about this if you’re willing, since 16 months should be plenty of time to form a daily habit if you’re doing something very consistently (as it sounds like you are) and doing it at the same time, location, in the same way, etc.

    For a closely-related example from my experience: For all of my life until recently I’ve been very inconsistent about flossing. It’s one of those things that seems vaguely important but really isn’t very pressing. A couple of months ago, though, I decided I really wanted to floss every night, and resigned myself to taking the extra few minutes out of my day, which had been my big obstacle (I didn’t want to give up any time to it). I began flossing every day, just before brushing my teeth, as soon as I went to the bedroom to get ready for bed. Within just a few weeks, it was an ingrained habit–I never forget about it these days. One advantage I had, though, is that I’ve brushed my teeth every night for pretty much my whole life, so adding flossing isn’t hard because I’m always facing the mirror in the bathroom before bed every evening.

  20. Katherine  •  Jul 16, 2012 @5:18 am

    Huge thanks for this article – and particularly the link to the research paper – exactly what I needed to inform a research project I am designing – and was having difficulty rationalising/ justifying how long I would send text message reminders for medication adherence – this is a life-saving article for me – thanks a million

  21. djay  •  Jan 14, 2013 @3:22 am

    Hi, Luc, just came across this again. Just an update to let you know that it’s been over two years and my December 2010 resolution is still not quite automatic. I still need to think about it each time although with less force than before. No, I do not do it at the same time every night. There is nothing I do at the same time any time. Clearly there is a discipline issue at work in my psyche. In the meantime, I am tackling two new resolutions, one, to get to bed by midnight (which I missed this evening as it is already 2:17 am) and two, to practice my viola every day, especially necessary since I am performing a Bach cello suite solo in mid-June. We’ll see if that is motivation enough. It’s good to see that you are still in touch with the world with all you do. Sincerely, Denise

  22. djay  •  Jan 14, 2013 @7:58 am

    It just came to me: I have resisted routine and struggled with schedules all my life. Clearly, your polar opposite. It’s amazing that I have gotten anything done.

  23. Luc  •  Jan 14, 2013 @1:09 pm

    Hi Denise,

    Thanks for the update. It sounds like you’ve been putting in a lot of effort, which I have to admire.

    About making habits more automatic, you might be interested in checking out the posts I’ve written mentioning Charles Duhigg, whose book The Power of Habit: Why We Do What We Do in Life and Business has some really interesting reporting. The top two posts that come up are about cues, routines, and rewards, the breakdown Duhigg describes for habit development. The short version is this: if you can’t do the things you want to be doing at the same time every day, find another cue, for instance “As soon as I’m done eating dinner” or “First thing when I get home” or “Before watching any TV.” You probably already have a fairly consistent routine and a reward you know to expect (for instance, enjoying viola practice, or making improvements on the solo you’re practicing).

    Good luck, both with the habits and with the solo!


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