How Long Does It Really Take To Form A Habit?

The 21-day rule is used as a basis for forming habits. According to the rule, it takes 21 days to form a habit. Refinery29’s Molly Longman debunks the 21-day rule, claiming it as a myth. According to them, the rule is a misinterpretation of Maxwell Maltz’ work in Psycho-Cybernatics. Matlz noticed that a patient would take 21 days to adjust to a change in their body (whether it was a nose job or amputation). It wasn’t 21 days exactly, but a minimum of 21 days. In addition to the misinterpretation, research also discredits this known rule, as Refinery29 details:

Research summarily discredits the “21-day rule.” Phillippa Lally, PhD, a senior researcher at University College London, published a study that found it actually takes an average of 66 days — more than two months – to form a habit. Lally also reported that the amount of time before a new behavior feels automatic can range between 18 and 254 days.

“We don't really know what predicts the variation in times,” Lally says. But she does have a hunch: “It’s likely easier to consider that [a habit] feels automatic when it's a simpler behavior," Lally says. Drinking a glass of water in the morning requires less work than starting to exercise regularly, for example; so you may feel as though you're able to incorporate the former into your routine more quickly than the latter.