Dias para criar hábito
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The Habit Creation Days calculator estimates time required to establish a routine based on Lally's 2010 study, which found the average period is 66 days, not 21, as commonly believed. The calculation considers daily consistency and habit complexity, adjusting duration based on mental effort and contextual factors.
Use this tool when starting a new habit, such as workouts, healthy eating, or daily reading. It helps set realistic goals to avoid frustrations from unrealistic change expectations. The result shows a range (e.g., 58 to 73 days) based on your persistence history.
Cautions: duration varies with individual discipline, environment, and habit difficulty. This calculator does NOT predict outcomes for forced habits against will or without motivation. Lally's study used a sample of 96 people, but results may diverge in larger groups or different contexts.
Frequently asked questions
Why 66 days instead of 21?
The 21-day myth stems from outdated studies. Lally (2010) analyzed 96 participants and found the actual average is 66 days, varying by habit.
Does the calculator consider my consistency history?
Yes. You input how many days you've practiced the habit, and it adjusts the final estimate accordingly.
Works for all habit types?
No. Simple habits (e.g., drinking water) take less time than complex ones (e.g., learning piano). The tool asks you to rate difficulty.
Must I use it daily for accuracy?
Ideally, yes. Prolonged breaks may invalidate the average, as Lally's study assumes continuous practice.