You’ve probably heard the saying: “It takes 21 days to form a habit.” It sounds like a quick, convenient timeline, but is it true? Let’s dig into where this idea
came from, what science says about it today, and how you can work on forming habits that stick—whether they take 21 days or a little longer.
The Origins of the 21-Day Habit Theory
The idea that habits form in 21 days traces back to the
1950s when Dr. Maxwell Maltz, a plastic surgeon, noticed something interesting about his patients. After undergoing surgery, it often took his patients about 21 days to adjust to their new appearance or recover from the loss of a limb. Dr. Maltz wrote about this observation in his book Psycho-Cybernetics, suggesting that it takes 21 days for people to adapt to major changes.
Over time, this idea was generalized—and simplified. What started as an observation about mental adjustment became a catchy mantra about habit formation. But here's the catch: Dr. Maltz never claimed that 21 days was a hard-and-fast rule. He merely noted a trend in his specific field.
What Science Says Today
Modern research paints a more complex picture. A 2009 study from University College London found that, on average, it takes 66 days to form a habit—but that number can vary greatly depending on the habit and the individual. For instance:
Simple habits (like drinking a
glass of water with breakfast) might take just a few weeks to feel automatic.
More complex habits (like exercising daily or meditating) often take several months to become second nature.
The truth is, forming a habit depends on several factors:
Your starting point: Are you building on an existing routine, or starting from scratch?
The habit itself: Some habits are easier to form than others because they’re simpler or more rewarding. Atomic Habits, is a
wonderful book on this topic. Consistency: Repetition is key, but it needs to be realistic. Missing a day or two won’t ruin your progress, but regularity matters.
Your motivation: A habit tied to a meaningful goal is more likely to stick than one you’re doing out of obligation.
Why 21 Days Still Holds Some Value
While 21 days might not work for every habit, the
concept can still be helpful. Three weeks is a manageable chunk of time for most people to commit to, and it's long enough to start seeing results. Once you hit that mark, you may feel encouraged to keep going—and that momentum is often what helps a habit stick.
How to Form a Habit (No Matter How Long It
Takes)
Whether it’s 21 days or 66, here’s how to make the process easier:
1. Start Small
Break your habit into bite-sized steps. Instead of saying,
“I’ll exercise for an hour every day,” start with 10 minutes a few times a week.
2. Tie It to an Existing Routine
Pair your habit with something you already do daily. For example, if you want to floss, do it right after brushing your
teeth.
3. Track Your Progress
Use a habit tracker or app to keep yourself accountable and celebrate small wins along the way.
4. Be Flexible
Life happens! If you miss a day, don’t give up. Habits form through consistency over time, not perfection.
5. Focus on Why It
Matters
Tie your habit to a larger goal or value. Want to start meditating? Remind yourself that it helps you feel calmer and more focused.
Some habits might feel natural after three weeks, while others could take months to become routine. Instead
of fixating on the timeline, focus on the process and the progress you’re making.
After all, the real goal isn’t just to form a habit—it’s to create lasting change. What matters most is that you keep moving forward.
