How long does it take to form a habit?
You've probably heard 21 days. The real answer is longer, it varies a lot from person to person, and it's far more forgiving than the number suggests. Here's where 21 days came from, what researchers found when they actually measured it, and what makes a new habit stick.
Where 21 days came from
The number traces back to Maxwell Maltz, a plastic surgeon who wrote a self-help book called Psycho-Cybernetics in 1960. He noticed that his patients seemed to take around three weeks to get used to a new face, and that people who lost a limb went on feeling it for about as long. From that he suggested it takes at least about 21 days for an old mental picture of yourself to give way to a new one.
That was an observation from his practice, not a study, and it was about getting used to a change rather than building a habit. Over the following decades the "at least about" fell away, and "21 days to form a habit" became one of those things everybody knows.
The trouble with it isn't only that it's wrong. It's that it sets you up to quit. If you believe a habit should be automatic by day 21, then day 22, when it still takes effort, feels like failure.
What the research found
Phillippa Lally and her colleagues at University College London measured it properly. In a study published in the European Journal of Social Psychology in 2009, they asked 96 volunteers to pick one new daily behavior, something to eat, drink or do in response to a cue that came up every day, like a glass of water with lunch or a run before dinner. Every day for twelve weeks, each person rated how automatic the behavior felt.
For the people whose results fit the researchers' model, the median time to reach their plateau, the point where it stopped getting any more automatic, was 66 days. The range was enormous: from 18 days to an estimated 254. Simpler behaviors tended to get there sooner than harder ones like exercise.
New habits are what you're trying. Old habits are who you are.
Derek Sivers, How to Live
So the honest answer is about two months for many people, and anywhere from a few weeks to most of a year depending on you and on what you're trying to make automatic. If yours is taking longer than you hoped, you're not doing it wrong. You're in the middle of the range.
Missing a day doesn't send you back to the start
The most useful finding in Lally's study is easy to miss. Skipping the behavior once didn't materially affect how the habit formed. The people who didn't build a habit were the ones who were inconsistent again and again, not the ones who missed the odd day.
That matters because the all or nothing feeling, "I broke the streak, so what's the point", ends more habits than any single missed day. The writer James Clear has a rule of thumb for this: never miss twice. One gap is life. Two in a row is the start of a new pattern.
What starts as an excuse can easily become a habit. Don't let a bad day become a lifestyle.
James Clear, 3-2-1 Newsletter
Tie it to something that already happens
Habits form when the same action is repeated in the same situation, until the situation starts the action for you. Wendy Wood, a psychologist at the University of Southern California, found in a diary study with Jeffrey Quinn and Deborah Kashy that around 43 percent of what people did each day was habitual: done in the same place, almost daily, often while thinking about something else.
The flip side showed up when Wood and her colleagues followed students who transferred to a new university. Their habits, like exercising or reading the paper, only survived the move when the setting around them stayed similar. Change the cue and the habit loses its trigger.
So give your new habit a cue that already happens every day, and write it down as a plan: "After I pour my morning coffee, I'll do two minutes of stretching." "When I sit down on the train, I'll read ten pages." This is the same if-then planning from our post on how to stop procrastinating, and it works for the same reason: the decision is already made before the moment arrives.
Sometimes all you need for exceptional results is average effort repeated for an above-average amount of time.
James Clear, 3-2-1 Newsletter
Make it small enough to do on a bad day
A habit only forms if you repeat it, and you only repeat what you can do on your worst day as well as your best. So start smaller than feels worthwhile. One push-up. One sentence in the journal. Shoes on and out the door, even if you walk around the block and come back.
Just lace up your shoes and get out the door.
Leo Babauta, Zen Habits
Wood calls the other half of this friction. Small obstacles shape what we do more than we like to admit. Leave the running shoes by the door and the guitar out of its case. Put the cookies on a high shelf. Make the thing you want to do the easiest thing in the room, and the thing you don't a little more of a hassle.
How you'll know it's a habit
Not by counting days. By noticing that you've started doing it without deciding to, and that skipping it feels a bit odd. That's what the volunteers in Lally's study were rating: not how often they did it, but how automatic it felt.
Until then, expect it to take some effort, and don't read that effort as a sign it isn't working. The early weeks run on intention. If you need help getting through them, our post on how to stay motivated when the excitement wears off is about exactly that stretch.
Questions
Does it really take 21 days to form a habit?
No. The 21 days figure comes from Maxwell Maltz, a plastic surgeon who observed in 1960 that his patients took about three weeks to get used to changes. It was never a measurement of habits. When researchers at University College London measured habit formation, it took a median of 66 days, with a very wide range.
How long does it take to form a habit, according to research?
In Phillippa Lally's 2009 study at University College London, the median time for a new daily behavior to become automatic was 66 days. Some people got there in 18 days and some were estimated to need around 254. Simpler behaviors tended to become automatic faster than harder ones like exercise.
Does missing a day ruin a habit?
No. In Lally's study, missing a single opportunity did not materially affect how the habit formed. What got in the way was being inconsistent over and over. The practical rule is to never miss twice in a row.
Why do some habits take longer to form than others?
Harder and more complicated behaviors take longer to become automatic than simple ones. A habit also forms faster when it has a clear, reliable cue, such as a time of day or something you already do every day, and slower when the situation around it keeps changing.
How do I make a new habit stick?
Tie it to a cue that already happens every day, make it small enough to do on a bad day, make it easier to do than not to do, and if you miss a day, start again the next one. Expect it to feel like effort for a few weeks at least.
Keep reading
Start today with something good.
Set it up once. Dailies takes it from there.
