Depending on the behavior, it may become automatic for you in about 66 days. Some habits may be more challenging than others, but persistence and consistency do help to develop new ones.

Whether you want to develop a new habit or break an old one, it can be easier said than done. But how long does it actually take to make a change in behavior?

Some studies say under 20 days, while others say nearly 9 months. With such a wide variation, it may feel intimidating to even consider starting a new habit, but we will provide you with concrete steps to help you reach your goals.

According to an older study, it takes 18 to 254 days for a person to form a new habit. But other studies have reported that, on average, it can take 66 days for a new behavior to become automatic.

These studies have highlighted a range of variables in habit forming that make it challenging to establish a one-size-fits-all answer.

According to a 2024 systematic review, emerging evidence suggests that it can take approximately 2 months (around 60 days) to form a new habit. However, it varies significantly among individuals and the complexity of the habit.

Some people are more adept at forming new habits than others. A consistent routine of any kind isn’t for everyone, and that’s OK.

If asked how long it takes to form a habit, many people will respond “21 days.”

This idea can be traced back to Dr. Maxwell Maltz’s book “Psycho-Cybernetics,” published in 1960. Maltz didn’t make this claim but rather referenced this number as an observable metric in both himself and his patients at this time.

Maltz wrote: “These, and many other commonly observed phenomena, tend to show that it requires a minimum of about 21 days for an old mental image to dissolve and a new one to gel.”

As the book gained popularity and millions of copies were sold, this situational observation became widely accepted as fact.

According to an older 2012 study, habits are actions triggered automatically in response to cues associated with their performance. For example, when you get into your car, you automatically put on your seat belt. Most people don’t think about doing it or why.

That might sound simple, but habits are multifaceted, not simple stimulus-response behaviors, and involve multiple signaling mechanisms in the brain.

Your brain likes habits because they’re efficient. Automating common actions frees up mental resources for other tasks.

Habits don’t “stick” by chance. They’re the result of psychological and physiological factors that have developed over time.

When you repeat an action in the same setting, your brain starts to connect the context with the behavior. Over time, this link becomes automatic.

Psychologically, consistency and strong cues are most important. Biologically, your brain’s reward and memory circuits strengthen these connections, making the behavior feel almost second nature.

Key factors behind habit formation include:

  • Repetition in context: Performing the same action in the same setting reinforces the connection.
  • Cues and triggers: Small signals (such as time of day, location, or mood) prompt the behavior automatically.
  • Brain circuits: The basal ganglia help shift behaviors from conscious choices into automatic routines.
  • Reward reinforcement: Positive outcomes (relief, pleasure, progress) motivate the brain to repeat the habit.
  • Stability builds strength: The more consistent the environment, the faster habits solidify.

The brain likes efficiency and familiarity. Pleasure-based habits are particularly difficult to break because enjoyable behavior prompts your brain to release dopamine.

Dopamine is the reward that strengthens the habit and creates the craving to do it again.

As with many things in life, the first step is to become more aware of your habits so you can develop strategies to change them.

One strategy is to identify the places, people, or activities that are linked in your mind to certain habits, and then change your behavior toward those.

For example, if you have a substance use disorder, you can be deliberate about avoiding situations where you’d be more likely to be around the substance. This can help you achieve your goal of abstaining from using that substance.

Another strategy is to replace a bad habit with a good one. For example, instead of snacking on potato chips, consider swapping for unsalted, unbuttered popcorn. Instead of reaching for a cigarette, consider trying a new flavor of chewing gum or a flavored hard candy.

Getting specific and making SMART goals, often used in fitness, is also helpful.

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It can take anywhere from 18 to 254 days for a person to form a new habit, and an average of 66 days for a new behavior to become automatic.

There’s no one-size-fits-all figure, which is why this time frame is so broad. Some habits are easier to form than others, and some people may find it easier to develop new behaviors.

There’s no right or wrong timeline. The only timeline that matters is the one that works best for you.