# 21 Days Challenge > 21-day habit formation and breaking tracker with reminders and progress visualization. (iPhone/iPad app by Devashish Puri.) - Source: https://appshunter.io/ios/app/21-days-challenge/id1564581856 (this page in markdown: same URL + `.md`) - Developer: [Devashish Puri](https://appshunter.io/developer/1563049396) - Category: Health & Fitness, Productivity - Price: Free - Rating: 5.00/5 from 4 App Store ratings · 1 written reviews indexed - Age rating: 4+ - Requires: iOS 9.0 · 36 MB - Languages: English - Released: 2021-04-25 - Data updated: 2026-06-10 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/21-days-challenge/id1564581856/reviews.md ## What is 21 Days Challenge? Ever wondered how long does it take to break a habit? Scientists and leading psychology research suggest that it takes us around 21 days to break or form a new habit. This means doing a good thing (eating clean, exercising daily) can become your habit if done 21 days in a row. And Bestselling Book “Power of Habit by Charles Duhigg” suggests that an old bad habit cannot be extinguished in a day, but can only be replaced with a new good habit in 21 days period. So if you want to Quit Smoking? Lose Weight by eating clean? Quit eating junk food? Exercise daily? Go to Gym daily? Just do it for 21 days straight and our app allows you to record your golden age of lifestyle transformation. How does it work? To transform your lifestyle and create new good habits : Add a new goal that you want to pursue Replace it with a bad habit that you want to quit or extinguish Set reminder for the time you may want to be reminded Tap on Mark as Completed if you did it and if you couldn’t do it somehow, restart it! New Habits You Can Build with our App 1. Quit Smoking 2. 21 Days of No Fap 3. 21 Days of No Sugar 4. 21 Days of Intermittent Fasting 5. 21 Days of Eating Clean 6. 21 Days of Reading a book 7. 21 Days of Being Early Bird 8. 21 Days of Code 9. 21 Days of Journaling 10. 21 Days of Yoga Features that you may like 1. Powerful reminders with flexible scheduling 2. Updating goals doesn’t take more than a minute 3. Create a new avatar for your new lifestyle 4. Replace your bad habits with new habits 5. Calendar view to visualize your progress 6. Animations to lighten up the mood ## Key features - 21-day habit formation - Goal setting and tracking - Replace bad habits with good ones - Customizable reminders - Calendar progress visualization - Avatar creation ## Recent user reviews (1 of 1) All indexed reviews: https://appshunter.io/ios/app/21-days-challenge/id1564581856/reviews.md ### 5/5 — Great app! *2024-12-16* I like how simple and forward the app is. Perfectly designed for practical daily use. I’ve experimented with a lot of apps and this one has helped me the most by far. I refuse to restart the streak. Great app. ## Frequently asked questions about 21 Days Challenge ### What is the core concept behind 21 Days Challenge? The app is based on the psychological principle that it takes approximately 21 days to form or break a habit. It encourages users to commit to a new behavior or quit an old one for this duration to establish lasting change. ### How does 21 Days Challenge help users track progress? Users can mark their daily progress as completed or restart if they miss a day. The app features a calendar view that visually represents the user's streak and overall progress towards their 21-day goal. ### Can 21 Days Challenge be used to quit bad habits? Yes, the app is designed to help users replace old, undesirable habits with new, positive ones. Users can set a bad habit they wish to quit and then focus on building a new habit to replace it over the 21-day period. ### What kind of reminders does 21 Days Challenge offer? The app provides powerful and flexible reminders with customizable scheduling options. These reminders help users stay on track with their chosen habits and goals throughout the 21-day challenge. ### Does 21 Days Challenge have ads? No, 21 Days Challenge is ad-free, providing an uninterrupted user experience focused on habit formation and personal growth. ### What devices is 21 Days Challenge available on? 21 Days Challenge is available for iPhone and iPod devices, indicated by its supported devices list. ### How often is 21 Days Challenge updated? The app was last updated on May 30, 2021, with version 1.1. This suggests a moderate update frequency, with the developer actively maintaining the application. ### What is the age rating for 21 Days Challenge? 21 Days Challenge has an age rating of 4+, making it suitable for a wide range of users interested in self-improvement. ## Version history (last 2 releases) ### 1.1 — 2021-05-30 Notification on Remind Time ### 1.0 — 2021-04-26 No release notes. ## More apps by Devashish Puri - [Alankar / Palta maker](https://appshunter.io/ios/app/alankar-palta-maker/id1563049394) - [Add Letter - Newsletter Reader](https://appshunter.io/ios/app/add-letter-newsletter-reader/id1667150186) All apps by Devashish Puri: https://appshunter.io/developer/1563049396 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*