How long does it take to form a habit? What studies show

Lally and colleagues at University College London asked 96 volunteers to pick a healthy eating, drinking or exercise behaviour and do it once a day in the same context, such as “after breakfast”. For 84 days they recorded whether they did it and how automatic it felt, using a standard habit questionnaire.

Automaticity rose quickly at first and then levelled off, following a curve rather than a straight line. For the people whose data fitted that curve well, the time to reach 95% of their personal plateau ranged from 18 to 254 days, with a median of 66.

Two further findings are worth holding on to. Not everyone’s data fitted a clean curve, which is a reminder that habits form messily. And missing a single opportunity did not materially affect the process. A missed day is not a reset.

Sources1Source 1Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W., & Wardle, J. (2010). How are habits formed: Modelling habit formation in the real world. European Journal of Social Psychology, 40(6), 998–1009.

A 2024 systematic review and meta-analysis by Singh and colleagues gathered 20 studies with 2,601 participants, covering physical activity, healthy eating, flossing, drinking water and more. The four studies that reported how long habits took found median times of 59 to 66 days and mean times of 106 to 154 days, with individual cases ranging from 4 to 335 days. Habit strength rose reliably after interventions.

The review also found hints about what speeds things up: habits practised in the morning and habits people chose for themselves tended to be stronger. The authors are candid that most of the studies had a high risk of bias and the total number was small, so treat these as leads rather than rules. The consistent message is that two months is a reasonable first horizon and that longer is normal.

Sources2Source 2Singh, B., Murphy, A., Maher, C., & Smith, A. E. (2024). Time to form a habit: A systematic review and meta-analysis of health behaviour habit formation and its determinants. Healthcare, 12(23), 2488.

It helps to know what is forming during those weeks. In their review in the Annual Review of Psychology, Wood and Rünger describe habits as learned links between a context and a response. They form as people repeat the same action in the same situation while pursuing a goal. Once formed, the context triggers the action with little thought, and habits become the efficient default that runs alongside deliberate choices. People even tend to infer from how often they do something that they must have meant to.

Neal, Wood and Quinn point to diary studies showing that much of everyday behaviour is this kind of repetition in stable settings. That is why the context matters so much. “Exercise more” gives the brain nothing to attach to. “Walk round the block after I put the kettle on in the morning” does.

It also explains why motivation alone is a poor foundation. Motivation rises and falls with mood, energy and the weather. A habit, once formed, does not need you to feel motivated; the cue does the work. That is the real prize of the first two months: not willpower, but getting to the point where you no longer need it. It is also why rewards and streaks, which run on motivation, are an uneasy fit for habit building, as we explore in rewards, streaks and motivation.

Sources3Source 3Wood, W., & Rünger, D. (2016). Psychology of habit. Annual Review of Psychology, 67, 289–314.4Source 4Neal, D. T., Wood, W., & Quinn, J. M. (2006). Habits—A repeat performance. Current Directions in Psychological Science, 15(4), 198–202.

Put the findings together and a practical recipe emerges. None of it is glamorous, and all of it works with how habits form rather than against it.

• Pick one behaviour and attach it to an existing, reliable cue: after brushing your teeth, when you sit down on the train.
• Make it small enough that you can do it on a bad day.
• Keep the context the same: same time, same place, same trigger.
• Expect it to take around two months, and longer for harder behaviours.
• If you miss a day, do it the next day; the research says one gap barely matters.
• Choose something you want to do: self-chosen habits tended to be stronger.

Sources1Source 1Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W., & Wardle, J. (2010). How are habits formed: Modelling habit formation in the real world. European Journal of Social Psychology, 40(6), 998–1009.2Source 2Singh, B., Murphy, A., Maher, C., & Smith, A. E. (2024). Time to form a habit: A systematic review and meta-analysis of health behaviour habit formation and its determinants. Healthcare, 12(23), 2488.3Source 3Wood, W., & Rünger, D. (2016). Psychology of habit. Annual Review of Psychology, 67, 289–314.

The same mechanism that lets you build a walking habit lets an app build one for you. A phone sits in almost every context of the day, and anything designed to be opened “just for a moment” can attach itself to waiting, boredom, lying in bed and the first minute after waking. Those habits were never chosen, which is exactly why they are hard to notice. We look at the design side of this in how games become habits.

Breaking an unwanted habit is harder than starting a new one. In two diary studies and an experiment, Quinn and colleagues found that strong bad habits were best controlled by vigilant monitoring, actively watching for the slip and telling yourself not to. Other strategies that work against temptations did not help much against strong habits.

That is one reason a short break from your phone rarely rewires anything on its own. When the break ends, the cues are all still there. Our look at whether a digital detox works found the same pattern in the trials.

The healthier alternative is to decide where play goes. A single daily board after breakfast or on the commute home is a small, chosen ritual with an end. It can become a habit you like having. What a well-made game should not do is try to claim every other gap in your day as well; our piece on daily rituals that do not demand you explains why we built OutBrick’s daily bonus so that a missed day is simply a missed day.

Sources5Source 5Quinn, J. M., Pascoe, A., Wood, W., & Neal, D. T. (2010). Can’t control yourself? Monitor those bad habits. Personality and Social Psychology Bulletin, 36(4), 499–511.3Source 3Wood, W., & Rünger, D. (2016). Psychology of habit. Annual Review of Psychology, 67, 289–314.