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Comparison

66 Challenge vs Go Gray | Reduce Screen Time

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
66 Challenge
66 Challenge

Build habits in 66 days

Free
📊 Productivity
★ 5.05 ratingsView app →
Go Gray | Reduce Screen Time
Go Gray | Reduce Screen Time

Grayscale to reduce phone use

Free
📊 Productivity
No ratingsView app →
About

66 Challenge

Build lasting habits with a science-backed system designed to guide you through a 66-day journey. Track daily progress, visualize your transformation, and stay motivated with social features and achievements. Transform your life one habit at a time.

Highlights
  • Daily habit tracking
  • Progress visualization
  • Streak protection
  • Social feed and squads
  • Customizable reminders
  • Achievement badges
Features
Read full description

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

About

Go Gray | Reduce Screen Time

Features
Read full description

Go Gray helps you cut phone addiction with grayscale mode and Screen Time tools. See the colour in the world again — turn bright, addictive apps dull so your phone becomes a tool, not a reward system. Features: • Grayscale mode to make distracting apps less rewarding • Screen Time awareness with clear pickup and usage stats • Shields and schedules via Apple’s Family Controls • Simple tools to help you stay in control of your phone Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://www.gogray.today/privacy

Screenshots

66 Challenge4 screens
Go Gray | Reduce Screen Time4 screens

Verdict

The call

The clearest difference is update cadence: Go Gray | Reduce Screen Time at every 2 days against 66 Challenge's every 5 days. 66 Challenge's advantage is device support (3 vs 1) and iOS requirement (13.0 vs 16.0). On price, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. 66 Challenge sells 3 in-app purchases, starting at $3.99 per month and Go Gray | Reduce Screen Time sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

66 Challenge ships an update every 5 days, Go Gray | Reduce Screen Time every 2 days. Both last shipped on October 31, 2026.

Scorecard3 real differences · 6 level
66 Challenge versus Go Gray | Reduce Screen Time: the parameters behind the verdict, then further details
Parameter66 ChallengeGo Gray | Reduce Screen Time
PriceFreeFree
Rating5.0 (5 ratings) — better—
Number of ratings5 — better—
Update frequencyEvery 5 daysEvery 2 days — better
AdsNoNo
In-app purchasesYesYes
MonetizationFreemium—
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS13.0 — better16.0
Further details — not scored
Size18 MB18 MB
Age rating12+4+
DeveloperMoad Ghajjate El Falatareh studios inc

In-app purchases

3 purchases

66 Challenge

Subscriptions2
  • Pro Monthly7 Days trial$3.991 Month
  • Pro Annual7 Days trial$29.991 Year
One-time1
  • Pro Lifetime$59.99
2 purchases

Go Gray | Reduce Screen Time

Subscriptions2
  • Go Gray Pro Monthly$2.991 Month
  • Go Gray Pro Yearly$24.991 Year

Questions

Is 66 Challenge free?
66 Challenge is free to download, with in-app purchases available.
Is Go Gray | Reduce Screen Time free?
Go Gray | Reduce Screen Time is free to download, with in-app purchases available.
Do 66 Challenge or Go Gray | Reduce Screen Time have ads?
Neither 66 Challenge nor Go Gray | Reduce Screen Time shows ads.
Which is updated more often, 66 Challenge or Go Gray | Reduce Screen Time?
66 Challenge ships an update every 5 days, and Go Gray | Reduce Screen Time every 2 days. Most recently, 66 Challenge was updated on October 31, 2026 and Go Gray | Reduce Screen Time on October 31, 2026.

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