Debunking the 21 Days Rule: The Truth About Habit Formation

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The 21 Days Rule: Fact or Fiction?

We’ve all heard of the 21 Days Rule – the idea that it takes approximately 21 days to form or break an old one. But is this rule really applicable to habit formation in all areas of life? Let’s dive deeper into this popular belief and examine its validity.

The Origins of the 21 Days Rule

The notion of the 21 Days Rule can be traced back to a book published in the 1960s by plastic surgeon Dr. Maxwell Maltz. In his book, he claimed that it takes a minimum of 21 days for patients to adjust to their new appearance after plastic surgery. Over time, this idea was extrapolated and applied to various habits and behaviors.

21-day rule, a myth

However, research has shown that the 21-day rule is a myth. In a study published in the European Journal of Social Psychology, researchers found that it takes an average of 66 days for a new behavior to become a habit. However, the time it takes to form a new habit can vary widely depending on the behavior and the individual.

The Reality of Habit Formation

While the 21 Days Rule may sound appealing, research suggests that it is not universally applicable. A study conducted by the University College London found that it actually takes an average of 66 days for a habit to become automatic. However, this timeframe can vary widely depending on the individual and the complexity of the habit.

Furthermore, it’s important to note that not all habits are created equal. Simple habits, such as drinking a glass of water every morning, may be easier to form within a shorter timeframe. On the other hand, complex habits, like quitting smoking or starting a regular exercise routine, may require more time and effort.

Motivation for Change of Habits

Several factors can impact how long it takes to form a new habit. One of the most important factors is motivation. If you’re highly motivated to change a behavior, you’re more likely to stick to it and make it a habit. Another important factor is repetition. The more you repeat a behavior, the more likely it is to become automatic.

The Importance of Consistency

Regardless of the exact timeframe, one thing is clear – consistency is key when it comes to habit formation. Whether it takes 21 days or 66 days, the key is to stick with the new behavior consistently over time. This means being committed and disciplined, even when motivation wanes.

It’s also important to set realistic expectations. Breaking an old habit or forming a new one is not always a linear process. There may be setbacks along the way, and that’s okay. What matters is getting back on track and continuing to work towards the desired change.


While the  21-day rule may not be a one-size-fits-all solution, it does highlight the importance of consistency and perseverance in habit formation. Whether it takes 21 days, 66 days, or even longer, the key is to stay committed and keep working towards the desired change. So, if you’re looking to break an old habit or form a new one, remember that it’s a journey that requires patience and dedication.

Focusing solely on fixed timeframes like the 21-days rule or the 66-days rule for changing habits may overlook the essence of habit formation. Instead, the key lies in consistently sticking to the new behavior over time. By maintaining dedication and perseverance, habits gradually become ingrained into our routines, leading to sustainable change. It’s about embracing the process and committing to long-term growth rather than fixating on arbitrary timelines. Consistency, persistence, and patience are the true catalysts for habit transformation.

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