# 66 Challenge — Build habits in 66 days > Science-backed app for building lasting habits in 66 days. (iPhone/iPad app by Moad Ghajjate El Fal.) - Source: https://appshunter.io/ios/app/66-challenge/id6758270405 (this page in markdown: same URL + `.md`) - Developer: [Moad Ghajjate El Fal](https://appshunter.io/developer/1871890791) - Category: Productivity, Health & Fitness - Price: Free with in-app purchases - Rating: 5.00/5 from 5 App Store ratings - Age rating: 12+ - Requires: iOS 13.0 · 18 MB - Languages: American English - Released: 2026-02-05 - Data updated: 2026-09-04 - Monetization: freemium - User reviews in markdown: https://appshunter.io/ios/app/66-challenge/id6758270405/reviews.md ## What is 66 Challenge? Transform your life one habit at a time with 66 Challenge - the science-backed app that helps you build lasting habits in just 66 days. WHY 66 DAYS? Research shows it takes an average of 66 days to form a new habit. We've built the perfect system to guide you through every single day. KEY FEATURES: - Daily Habit Tracking - Mark your habits complete each day and watch your streak grow - Progress Visualization - See your 66-day journey unfold with beautiful progress tracking - Streak Protection - Stay motivated with streak counts and milestone celebrations - Progress Photos - Capture your transformation with optional daily photos - Friends & Social Feed - Follow friends, celebrate their wins, and stay accountable together - Squads - Join or create groups to challenge habits together - Achievements - Unlock badges as you hit milestones on your journey - Reminders - Never miss a day with customizable notifications BECOME UNDENIABLE Whether you want to exercise daily, read more, meditate, or build any positive habit - 66 Challenge gives you the structure, motivation, and community to make it stick. Start your 66-day transformation today. --- Terms of Use: https://spiffy-muskmelon-f8f.notion.site/Terms-of-Service-66-Challenge-2f456f682ccc8026ac42f9567c526f57 Privacy Policy: https://spiffy-muskmelon-f8f.notion.site/Privacy-Policy-66-Challenge-1e956f682ccc80f18d6ad0a347d8707f ## Key features - Daily habit tracking - Progress visualization - Streak protection - Social feed and squads - Customizable reminders - Achievement badges ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | Pro Annual | $29.99 | per year | | Pro Monthly | $3.99 | per month | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Pro Lifetime | $59.99 | one-time | ## Frequently asked questions about 66 Challenge ### What is the 66 Challenge app? 66 Challenge is a productivity app designed to help users build lasting habits over a 66-day period. It offers daily tracking, progress visualization, and community features to support users in their habit-forming journey. ### How does 66 Challenge help users build habits? The app utilizes a science-backed approach, suggesting 66 days as the average time to form a new habit. It provides daily tracking, streak protection, milestone celebrations, and optional progress photos to keep users motivated. ### Can I track habits with friends on 66 Challenge? Yes, 66 Challenge features a social feed where you can follow friends, celebrate their achievements, and stay accountable together. You can also join or create 'Squads' to challenge habits as a group. ### What are the subscription options for 66 Challenge? 66 Challenge offers 'Pro Monthly' for $3.99/month and 'Pro Annual' for $29.99/year. Both plans include a 7-day free trial. ### Is 66 Challenge available on multiple devices? Based on the supported devices, 66 Challenge is available on iPhone, iPad, and iPod, indicating compatibility with Apple's iOS ecosystem. ### How often is 66 Challenge updated? The app was last updated on August 18, 2026, with version 1.1.0. This suggests a relatively recent update, indicating ongoing development and support. ### What is the age rating for 66 Challenge? 66 Challenge has an age rating of 12+, making it suitable for users aged 12 and above. ### Does 66 Challenge have ads? No, 66 Challenge does not contain advertisements. The app is free to download and offers optional in-app purchases for premium features. ## Version history (last 5 releases) ### 1.1.1 — 2026-08-25 Fixed a bug where the day could advance twice in one evening. Reminders now stay on after reinstalling. New share card. Badges now reward your longest streak. ### 1.1.0 — 2026-08-18 Streak Shields so one missed day doesn't erase your progress. Friends and Squads are now free for everyone. Real stats and a 66-day calendar. Plus a pile of fixes — including one where new accounts could get stuck on Day 1. ### 1.0.8 — 2026-02-17 New updated screenshot previews of the app. ### 1.0.7 — 2026-02-12 More notification variety, performance improvements. ### 1.0.5 — 2026-02-10 Bug fixes and performance improvements on day tracking. ## Apps similar to 66 Challenge | App | Rating | Price | Category | | --- | --- | --- | --- | | [SyncTasks](https://appshunter.io/ios/app/synctasks/id6575384261) | 4.6 (343) | Free | Productivity | | [Monke - Habit Game](https://appshunter.io/ios/app/monke-habit-game/id6755640836) | 4.8 (1,932) | Free | Productivity | | [Easlo Experiments](https://appshunter.io/ios/app/easlo-experiments/id6743023810) | 4.6 (22) | Free | Productivity | | [WIP: Social Habit Tracker](https://appshunter.io/ios/app/wip-social-habit-tracker/id6755211115) | 4.8 (1,986) | Free | Productivity | | [TripleWhale](https://appshunter.io/ios/app/triplewhale/id1511861727) | 2.7 (29) | Free | Productivity | | [DailyHack](https://appshunter.io/ios/app/dailyhack/id6737768320) | 4.8 (104) | Free | Productivity | ## Related topics [30 days challenge with adastra](https://appshunter.io/ios/topics/30-days-challenge-with-adastra) · [66 streaks](https://appshunter.io/ios/topics/66-streaks) --- *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 2026-09-04.*