How Long Does It Take to Build a Habit?

If you ask people how long it takes to build a habit, a lot will say that it takes 21 days to form a habit, but research suggests otherwise. A study published in the European Journal of Social Psychology found that, on average, it actually takes 66 days to solidify a new habit—not just three weeks.

This study, made famous by James Clear’s book Atomic Habits, reveals that habit formation is a gradual process that depends on consistency, not just time.

Let’s explore what this means for you and how you can build lasting habits effectively.

The 66-Day Habit Study: What the Research Says

Researcher Dr. Phillippa Lally and her team at University College London studied 96 people as they attempted to form a new habit—such as drinking more water, eating fruit daily, or exercising regularly.

Here’s what they found:

• On average, it took 66 days for a behavior to become automatic.
• Habit formation ranged from 18 to 254 days, depending on the complexity of the habit and individual differences. For example, something like quitting smoking is more complex and may take longer than a simpler habit like drinking more water.
• Consistency mattered more than perfection. A key thing I learnt from reading James Clears book was that missing a day here and there didn’t derail long-term habit formation. You just have to get straight back to doing the habit you want to create.

The key takeaway? There’s no magic number, but two to three months of repetition is a realistic expectation for turning an action into a habit.  Starting out your journey with this expectation will hopefully make it a lot easier to stick to.

Why Does Habit Formation Take Time?

Your brain thrives on efficiency. Habits form when neural pathways strengthen through repetition. At first, new behaviors require conscious effort, but over time, they become automatic—like brushing your teeth or driving a car. In the study mentioned above, they used the term Automaticity.

Factors that can influence habit formation include:

• Complexity of the habit – Small habits like drinking water daily form faster than habits requiring more effort, like exercising regularly.
• Emotional & environmental triggers – Habits tied to specific cues (e.g., putting on running shoes before a workout) tend to stick more easily.
• Consistency over intensity – Doing a habit daily (even in small amounts) builds momentum more effectively than occasional intense efforts.

How to Make Habits Stick

​Now that we know habit-building takes time, how can you ensure success?

• Start small – Begin with an easy, achievable version of the habit (e.g., doing one push-up instead of a full workout).
• Pair it with an existing habit – Link your new habit to something automatic (e.g., practicing your balance whilst brushing your teeth). This is called Habit stacking.
• Track your progress – Keeping a habit tracker helps reinforce consistency and motivation.
• Focus on identity change – Instead of saying, "I need to run," say, "I am a runner."
• Be patient – If you miss a day, don’t quit. Habit-building is about progress, not perfection.

​Related: Read my blog post about dominos & the power of how doing something small adds up over time

Final Thoughts

 The 66-day rule isn’t a strict deadline—it’s a guideline showing that habit formation takes longer than we think, but is absolutely achievable with the right approach.

Rather than focusing on how fast you can form a habit, focus on being consistent. Small, daily actions will eventually lead to automatic behaviors that support long-term success.
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If you are wanting to create some healthy habits, but you have a few niggles or injuries holding you back, chiropractic care could be a good option. To see if chiropractic care is right for you, contact us.

P.S. Want a simple tip to help you create a new habit? watch the video below. This is one of my favourites.