Blog Fitness How Many Days to Break a Habit, According To Science?

How Many Days to Break a Habit, According To Science?

Trying to break a bad habit can be quite frustrating, particularly when it’s something you’ve done for several years. It can be even more challenging when you’re not sure how long it will take for a replacement behavior to stick.

Thankfully, science offers some insights into this. Research has shown that our brains are adaptable and can rewire themselves to form new patterns and behaviors (1). It won’t happen overnight and it certainly won’t be easy, but it’s definitely possible to break a habit and choose a better one.

Here’s what you need to understand to get rid of a bad habit.

Does it Really Take 21 Days to Break a Habit?

No, it doesn’t take exactly 21 days to break a habit. That’s just a myth.

The myth that it takes 21 days to break a habit may come from a self-help book that was published in the early 1960s by plastic surgeon Dr. Maxwell Maltz. 

He observed that his patients took approximately three weeks to adjust to their new appearance, but this was simply an observation, rather than any kind of scientific study.

Furthermore, becoming accustomed to a new appearance is not the same as breaking a habit.

If anything, the two are entirely opposite processes. Adjusting to a new appearance is a positive mental change and the patient is generally ready for this change, whereas breaking a habit involves resisting temptations and going against ingrained patterns of behavior.

On the plus side, the two are related in the sense that they both involve neuroplasticity – the ability of the brain to change and adapt (2). So while some habits may only take a few weeks to break (which is obviously well within the 21-day mark), others may require significantly longer.

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So, How Long Does it Actually Take to Break a Habit?

There’s no specific timeline for habit-breaking as it is a highly individualized process. Research has been conducted on how long it takes to form a new habit, but relatively little research has been conducted on how long it takes to break one.

According to a study published in the European Journal of Social Psychology, it takes an average of 66 days for a new behavior to become automatic (2). However, this can change depending on several factors, including:

The complexity of the habit: A simple habit, such as drinking water first thing in the morning, may become automatic more quickly than a complex one such as learning to meditate.

Personal commitment: The more determined you are to break the habit, the faster it’s likely to happen.

Frequency: How regularly you engage in the habit can also affect how quickly you can break it. The more often you do it, the more ingrained it will become in your routine.

The presence of triggers: If there’s a specific trigger that prompts you to perform the habit, it may take longer to break.

The reward: If the habit provides a strong reward (such as the pleasure of smoking a cigarette or eating junk food), it can be more challenging to break.

Support systems: The support of friends, family, or a coach can make a big difference in the speed and success of habit-breaking.

The assumption here is that by choosing a new behavior, you’re effectively replacing an old one.

how many days to break a habit  

For example, you have a habit of biting your fingernails when you’re anxious, but you decide to start chewing gum instead. It will take time for the new behavior of chewing gum to become automatic and replace the old habit of nail-biting.

Replacing a bad habit with a better one is a technique that is used in cognitive behavioral therapy that has been proven to be effective for breaking habits. It involves identifying the triggers and rewards associated with a habit and replacing them with healthier alternatives.

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However, it isn’t always possible to break a habit by simply replacing it with another behavior. For example, to break the habit of smoking, there are behavioral factors and a physiological component to consider. 

To overcome a gambling addiction, you’ll require a much deeper understanding of the underlying causes and triggers. 

In other words, you can’t simply replace these behaviors with healthier alternatives and you’ll need to address the root causes.

We discuss root causes in more detail in our article “Why Do I Overeat?

What Are the 6 Steps to Breaking a Habit?

The first step for getting rid of a bad habit is understanding something called the “habit loop”. You can then follow these steps to break it:

Step 1: Identify the Cue

The first step to breaking a bad habit is identifying the cue. What triggers you to engage in the unwanted behavior? Is it boredom, stress, or loneliness?

Unfortunately, identifying the cue isn’t always as easy as it sounds. Sometimes, cues can be hidden or subconscious. It may take some tracking over time before you are able to pinpoint your specific cue.

For example, on the surface, it may appear that when you’re anxious (a potential cue), you bite your nails, but upon closer inspection, you may realize that it’s only in certain situations this habit occurs. 

Perhaps it happens specifically when you’re in a crowded room or if you’re giving a presentation. You don’t bite your nails when you’re anxious in other situations, so the cue is not anxiety itself, but a specific trigger associated with it.

Read more: Thigh Workout Guide: 7 Effective Exercises for Building Leg Strength

Step 2: Recognize the Routine

Once you’ve identified the cue, you need to recognize the routine – the behavior you engage in as a result of the cue. This is generally the habit you want to break. With our nail-biting example, the routine is biting your nails.

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The routine/behavior is generally the most obvious part of the habit, but many people make the mistake of hyper-focusing on it when trying to break a habit.

Solutions such as wearing gloves or using bitter-tasting nail polish may stop the behavior under those conditions, but they won’t eliminate the habit completely.

People who are trying to break an addiction may also struggle with this step, oversimplifying the solution as simply quitting the drug. There’s often a wider, more complex set of circumstances that must be addressed, and it may necessitate seeking help from a qualified treatment provider.

Step 3: Find the Reward

Rewards play a crucial role in habits. They reinforce the behavior and increase the likelihood of it occurring again in the future.

For example, when you’re stressed, you eat chocolate and your brain releases dopamine (a neurotransmitter), which makes you feel good. This positive reinforcement strengthens the behavior, making it more likely that you will reach for chocolate again when faced with a similar situation.

Not only is this false, as dopamine is essential for several bodily functions in addition to pleasure, it also fails to address the underlying issue of the reason you engage in the habit. 

Therefore, rather than trying to eliminate dopamine entirely, you should focus on finding healthier alternatives that still provide a reward. For example, the next time you’re stressed, go for a walk or a run. You’ll end up hitting your activity target for the day and also feel good about taking care of yourself rather than choosing unhealthy options. 

how many days to break a habit  

Step 4: Identify What Drives the Behavior

To truly break a habit, you must understand why it exists in the first place. What purpose does it serve? Why do you engage in this behavior?

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In some cases, habits may be coping mechanisms that are used for dealing with stress, anxiety, or other underlying issues. By understanding the root cause of your habit, you can work toward addressing it and finding a healthier way of coping.

You can get more inspiration in this article about Healthy Habits to Start.

Step 5: Create a Plan

Once you’ve identified the cue, routine, and reward, and you understand the underlying cause of your habit, it’s time to create a plan. This should involve replacing the old habit with healthier alternatives and finding ways to address the root issue.

For example, if you have a habit of eating junk food when you feel stressed (cue), your routine could be to go for a walk or do some deep breathing exercises instead. This will still provide the reward of stress relief, but in a much healthier way.

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Your plan should include some elements of SMART goals – specific, measurable, achievable, realistic, and time-bound:

  • A specific goal could be to use a specific coping strategy such as taking a few moments of mindfulness or deep breathing in place of eating junk.
  • A measurable goal needs to be something you can concretely measure. For example, engage in 15 seconds of mindfulness or deep breathing every time your urge for junk food is triggered. 
  • An achievable goal could be to replace the junk food with your coping strategy on one or two episodes where you’re triggered every day. The key here is to do something you know you can do – the achievement will boost your momentum. That confidence and momentum will be there for you when you set more challenging goals. 
  • A realistic goal could be to replace junk food with a coping strategy you can use in different contexts. Setting a goal of going for a jog isn’t realistic when you’re sitting in a meeting or taking a test. Taking a few slow, mindful breaths? That can be done anywhere and nobody needs to even know you’re doing it. 
  • A time-bound goal could be to use your coping strategy in place of eating junk food for one day, then two days, then longer. Be sure to start small enough that you can achieve it and increase the time frame as you get better at it.  
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We show how you can implement a good plan in our article How to Make Working Out a Habit.

Step 6: Be Patient and Persistent

Breaking a habit takes time, effort, and patience. You may experience setbacks or lapse back into your old behavior, but it’s important that you don’t beat yourself up over it and recognize it as simply a part of the process.

Ideally, you should also have a support system in place to help keep you accountable and motivated. This could be your friends, family, or a support group you can join.

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how many days to break a habit  


  • Does it take 28 days to break a habit?

No, the 28-day habit myth is based on a misinterpretation of a self-help book from the 1960s. Research has shown that it takes an average of 66 days for a habit to form and during the process, you may break the previous bad habit. However, exactly how long it takes is dependent on the individual and the complexity of the habit.

  • Why does it take 90 days to change a habit?

The 90-day timeframe may be popular as it aligns with the typical length of a behavior change program or challenge. However, for some people, changing a habit can take longer than 90 days, while it may be quicker for others.

Setting a specific, measurable, and time-bound goal such as breaking a habit in 90 days can certainly help motivate you and enable you to track your progress, but it’s important to also focus on the process rather than only the end goal.

  • What are the 4 rules of habit?

The following four rules were first introduced by the author and productivity expert James Clear in his book “Atomic Habits” and have since become a popular framework for understanding how habits work:

  1. Make it obvious: Define the cue and make the desired behavior easy to start
  2. Make it attractive: Find ways to make the routine more appealing or enjoyable
  3. Make it easy: Reduce friction and make the habit as effortless as possible
  4. Make it satisfying: Ensure that the reward is satisfying enough to reinforce the behavior

These rules can be applied to both breaking bad habits and forming good ones.

  • What is the 3-day rule for breaking a habit?

The three-day rule is a popular concept that suggests if you can resist the temptation to engage in a habit for three days, it will be easier to break. However, there is limited scientific evidence supporting this idea and breaking a habit often requires more time and effort.

Rather than relying on a specific timeframe, you should focus on understanding the underlying cause of the habit and creating a plan to address it, together with support and patience. It’s important to remember that breaking a habit is a process and progress may not always be linear.

The Bottom Line

Breaking a habit is not easy, but it’s possible with the right approach. By understanding the habit loop, identifying your cues and routines, finding healthier rewards, and creating a plan to address the root cause, you can successfully break any unwanted behavior. However, it’s important to remember to be patient and persistent, and you shouldn’t hesitate to seek support if you need it.


This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!


  1. How to rewire your brain (2022,
  2. How are habits formed: Modelling habit formation in the real world. (2010,
  3. Neuroplasticity (2023,
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