Comparison

O vs CatDays

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

Head to head
About

O

This app helps you manage your weight and physical data. It collects information from body fat scales and your smartphone to calculate and store various health metrics.

Highlights
  • Body data collection
  • Health data analysis
  • Health data storage
  • Calculates health indices
  • Integrates with body fat scales
Features
Read full description

In a word: manage the user's weight and physical data Application introduction: APP is divided into three parts: body data collection, health data analysis and health data storage. collect body fat scale’s and smart phone APP data, calculate and store various health index of human's body.

About

CatDays

Track important dates with a customizable cat companion. Choose from various feline friends to count down to future events or count up days since past milestones. Receive gentle reminders and view your progress with home screen widgets.

Highlights
  • Countdown and count-up modes
  • Selectable cat companions
  • Customizable reminders
  • Home screen widgets
  • iCloud synchronization
  • Ad-free experience
Read full description

CatDays is a minimalist countdown and day counter app. Choose a cat for every day that matters. It’ll wait with you for what’s ahead and remember how far you’ve come. Whether you’re looking forward to something in the future or marking a journey already underway, leave the counting to a cat. Every time you open CatDays, it’ll be right there, counting with you. ・Two ways to count: down and up Count down the days until something ahead, or count up the days since something began. Birthdays, trips, anniversaries, exams, or every day since you gave something up—CatDays can keep track of them all. ・The days you’ve lived are worth keeping Every season of anticipation and perseverance deserves to be remembered. One-time countdowns automatically move to Memories after they end. When a chapter comes to a close, you can stop a count-up on the exact day it ended. If you want to keep going, you can bring it back and continue counting anytime. ・A cat of your own Every date can have its own cat. Give it a tap and it’ll strike a new pose and talk to you—every cat has a personality of its own, so each moment together feels a little different. ・Your cat will remind you when it matters When an important day is near or arrives, your cat will send a gentle reminder. It’ll also check in when a count-up reaches a milestone worth marking. Turn reminders on or off and choose your preferred reminder time in Settings—quiet and never intrusive. ・Home Screen widgets put your cat where you’ll always see it Choose from Small and Medium countdown widgets and select the dates you want to display. A Medium widget can also show up to three countdowns at once. Your cat will change poses from time to time, so every glance feels a little different. Tap a widget to jump straight to the details in CatDays—a companion you can see every day. Lock Screen widgets are available too, so you can check the day count without unlocking your iPhone. ・Cat calendar widgets for every day Choose from a variety of cat calendar widgets featuring month, today, and week layouts. Pick your favorite cat and let it keep you company on your Home Screen every day. ・Automatic iCloud sync Your countdown data can sync automatically through iCloud across devices signed in to the same Apple Account, so it stays with you when you switch phones. Your content is stored on your device and in your personal iCloud and is never sent to our servers. ・Clean, calming, and free from distractions No ads, no subscriptions, and no complicated setup. Open CatDays and all you’ll see are your cats and the days that matter to you. 【Meet the Cats】 Included for free: Coco. More cats can be unlocked from the Cat Shop in Settings. Each cat is a one-time purchase and yours to use forever—no subscription required. Want to bring several home at once? Choose a pack for a better value. 【About Purchases】 CatDays is free to download, with all core features included. Additional cat characters are available as one-time purchases with no subscription fees. You can restore previously purchased content anytime from “Restore Purchases” in Settings. Let a cat keep track of the days that matter. Privacy Policy: https://catdays.app/en/privacy/ Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

O3 screens
CatDays4 screens

Verdict

The call

The clearest difference is review sentiment: CatDays at 83% against O's 0%. O's advantage is in-app purchases (none vs 8) and iOS requirement (9.0 vs 17.5). On price, update cadence, ads and device support 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. CatDays sells 8 one-off in-app purchases. O asks for nothing beyond the download.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on October 19, 2026 and October 25, 2026 respectively.

Scorecard4 real differences · 6 level
O versus CatDays: the parameters behind the verdict, then further details
ParameterOCatDays
PriceFreeFree
Rating—4.3 (6 ratings) — better
Positive reviews0.0% of reviews83.3% of reviews — better
Number of ratings—6 — better
Update frequencyEvery 3 weeksEvery 3 weeks
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPod — betteriPhone
Requires iOS9.0 — better17.5
Further details — not scored
Size5 MB38 MB
Age rating4+4+
DeveloperShenzhen LINGXI Technology Co., LtdLychee Intelligence Co., Ltd.

Customer experience

O

Written reviews48 reviews
Positive0.0%
Neutral10.4%
Negative89.6%

CatDays

All ratings5 ratings
Positive80.0%
Neutral0.0%
Negative20.0%
Written reviews6 reviews
Positive83.3%
Neutral0.0%
Negative16.7%

In-app purchases

None

O

No in-app purchases

8 purchases

CatDays

One-time8
  • Leo$2.99
  • Luna$2.99
  • Tofu$2.99
Show 5 more
  • Ash$2.99
  • Milo$2.99
  • Pumpkin$2.99
  • Leo & Luna Pack$3.99
  • Original Cats Pack$4.99

Questions

Is O free?
O is free to download, with no in-app purchases.
Is CatDays free?
CatDays is free to download, with in-app purchases available.
Do O or CatDays have ads?
Neither O nor CatDays shows ads.
Which is updated more often, O or CatDays?
O ships an update every 3 weeks, and CatDays every 3 weeks. Most recently, O was updated on October 19, 2026 and CatDays on October 25, 2026.

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