21 Days vs Kaizen Personal Development
Price, ratings, monetisation and update history for both apps, side by side โ with what reviewers say about each.
21 Days
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Build a new habit in 21 days, starting small enough that you'll actually do it. Big goals are easy to drop. 21 Days starts you with a tiny action, about 2 minutes a day, and gives you a reason to come back tomorrow: a streak you don't want to break and a tree that grows with every check-in. โข Pick a habit and check in once a day โข Watch your seedling grow into a tree as you keep going โข Take a rest day when you need one, without losing your streak (2 per run) โข Forgot yesterday? You can still check it in today โข Medals on days 7, 14 and 21 โข Clear stats: current and best streak, success rate, last 7 days โข Share a card when you finish your 21 days โข Morning and evening reminders at times you choose โข Your data stays on your device. No account needed. โข In English and Thai FREE Up to 2 habits in progress at a time (finished habits don't count). 21 DAYS PREMIUM Up to 10 habits in progress, a reminder time for each habit, and Home Screen widgets. Premium is an auto-renewing subscription, billed monthly or yearly. The price is shown in the app in your local currency before you buy. Payment is charged to your Apple ID at confirmation of purchase. The subscription renews automatically unless it is turned off at least 24 hours before the end of the current period. You can manage or cancel it in your App Store account settings. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://teezer.cloud/legal/21days/privacy/ Start today, and let's get to day 21 together.
Kaizen Personal Development
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Get 1% better every day. Kaizen helps you build habits that actually stick โ based on the Japanese Kaizen method and the Atomic Habits principle. Instead of chasing goals, Kaizen helps you build a new identity: become the person who works out, reads, or meditates every day โ one small step at a time, 1% per day. YOUR TOOLS โข Identity-based habits: tie every habit to the person you want to become โข Top-3 daily planning: focus each morning on the three tasks that truly matter โข Evening review: reflect in 2 minutes on what went well โ and what to improve tomorrow โข Zen garden: watch your progress grow with XP, streaks, and a garden that thrives with you โข Focus timer: work with deep concentration in Pomodoro sessions, distraction-free WHY KAIZEN? ๆนๅ (Kaizen) means "change for the better." No radical overhauls, no all-or-nothing โ just small, daily steps that add up to big results. Getting 1% better every day makes you 37x better after a year. KAIZEN PRO Try Kaizen Pro free for 7 days. After that, flexible monthly or yearly billing, cancel anytime. Start today. Your future self will thank you. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is in-app purchases: 21 Days at none against Kaizen Personal Development's 3. Kaizen Personal Development's advantage is update cadence (every 6 days vs every 3 weeks) and iOS requirement (15.1 vs 17.0). On price, ads and device support there is nothing between them.
Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS
Both are free to download. Kaizen Personal Development sells 3 in-app purchases, starting at $9.99 per month. 21 Days asks for nothing beyond the download.
21 Days ships an update every 3 weeks, Kaizen Personal Development every 6 days. Both last shipped on October 24, 2026.
| Parameter | 21 Days | Kaizen Personal Development |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 3 weeks | Every 6 days โ better |
| Ads | No | No |
| In-app purchases | No โ better | Yes |
| Devices | iPhone, iPad | iPhone, iPad, iPod โ better |
| Requires iOS | 17.0 | 15.1 โ better |
| Further details โ not scored | ||
| Size | 18 MB | 48 MB |
| Age rating | 4+ | 4+ |
| Developer | Phaisan Thauaonsamut | Monica Dede Schmid |
In-app purchases
21 Days
No in-app purchases
Kaizen Personal Development
- Kaizen Pro Monthly7 Days trial$9.991 Month
- Kaizen Pro Yearly (Offer)3 Days trial$49.991 Year
- Kaizen Pro Yearly7 Days trial$69.991 Year
Questions
Is 21 Days free?
Is Kaizen Personal Development free?
Do 21 Days or Kaizen Personal Development have ads?
Which is updated more often, 21 Days or Kaizen Personal Development?
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