How Long Does a New Habit Take? Longer Than 21 Days, and More Forgiving

You have probably heard that it takes 21 days to form a habit. A study that followed real people for twelve weeks found a different, and more encouraging, story. This guide explains it and how to use it. It is general education, not medical advice or therapy.

A study in real life

In 2010, Phillippa Lally and colleagues at University College London published a study in the European Journal of Social Psychology. 96 university students each picked a new everyday habit, such as eating a piece of fruit with lunch or going for a run before dinner. They did it daily in the same situation for 12 weeks, and each day they rated how automatic it felt.

What they saw

• It took about 66 days on average. That was the typical time for the behavior to feel largely automatic, among people whose data fit the model.
• Individual times varied hugely. The fitted times ranged from 18 days to a predicted 254 days, extending beyond the 12 weeks of the study, which is why a single number does not describe everyone.
• Simple habits formed faster. Exercise habits took about one and a half times as long to become automatic as eating or drinking habits.
• A missed day was not a disaster. A single missed day had little effect on how automatic the habit became, although many missed days did lower how automatic it eventually felt.

Why this is good news

• Slow is normal. If a new routine still feels like effort after three weeks, nothing is wrong. That is typical.
• One slip does not undo it. Getting back on track the next day is what counts.
• Small steps count. Starting with something easy gives you a head start.

Caveats

• The participants rated their own habits. Automaticity is a feeling, and people may rate it differently.
• The group was small and self-chosen. The volunteers were university students who picked their own behaviors, and 82 of the 96 saw the study through.
• The 66 figure is an average. It is a guide, not a deadline.

Ways to make a habit stick

• Attach it to something you already do. After breakfast, after brushing your teeth, after you park.
• Keep it small at first. A five-minute walk is easier to repeat than an hour at the gym. Our guide to walking is a gentle starting point.
• Make it easy. Lay out your shoes, prepare the fruit, put the water bottle where you will see it.
• Write it down. A simple note or tick can make the effort visible.
• Be kind about setbacks. Feeling bad about a lapse rarely helps. Our guide to stress eating explores the link between feelings and food.

To sum up

New habits take longer than the popular myth says, and they are more forgiving than most of us fear. If you are in the middle of building one, give yourself time and keep showing up.

Sources

• Lally P, van Jaarsveld CHM, Potts HWW, Wardle J. How are habits formed: modelling habit formation in the real world. European Journal of Social Psychology, 2010;40(6):998-1009.
• British Psychological Society Research Digest, “How long does it take to form a habit?”, summary of the study.