System 911 vs Happy Kitty Calculator
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
System 911
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本 App 配合一个蓝牙无线按摩器使用，你可以通过你的手机控制你的按摩器，十分便捷。 主要功能： - 开关 - 力度 - 模式 - 按摩记录
Happy Kitty Calculator
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This is a cat-themed calculator featuring munchkin cats, Persian cats, ragdoll cats, and various AI-designed cats. Combined with exquisite hand-drawn designs, it makes every use delightful. The calculator not only looks adorable but also ensures precise calculations for every input. The button size is designed for quick calculations, ensuring ease of use. Users can customize backgrounds with options like landscapes, rooms, streets, and forests. The display area offers various styles and colors, along with adorable themed buttons and background colors, allowing users to create their own personalized, cute calculator. Additionally, we periodically release updates to add new content and features, ensuring users can enjoy the latest and most exciting changes! By using this application, you agree to our Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://www.termsfeed.com/live/f5f24d28-ed7f-4755-80c8-20a300f6a11f Terms of Service: https://docs.google.com/document/d/1WteUIp6cT0xQVK86647jO0a2gQvwk-pJ7jnqMJqM5kI/edit?tab=t.0#heading=h.y4qd89gjlri Contact the Development Team t47320@gmail.com
Screenshots
Verdict
The clearest difference is in-app purchases: System 911 at none against Happy Kitty Calculator's 1. System 911 also leads on iOS requirement (9 vs 15.6). Happy Kitty Calculator's advantage is update cadence (every 3 weeks vs every 6 weeks). On price, 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
Both are free to download. Happy Kitty Calculator sells 1 one-off in-app purchase. System 911 asks for nothing beyond the download.
System 911 ships an update every 6 weeks, Happy Kitty Calculator every 3 weeks. Both last shipped on October 25, 2026.
| Parameter | System 911 | Happy Kitty Calculator |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 6 weeks | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Devices | iPhone, iPod | iPhone, iPod |
| Requires iOS | 9 — better | 15.6 |
| Further details — not scored | ||
| Size | 29 MB | 59 MB |
| Age rating | 4+ | 4+ |
| Developer | 学新 黄 | HUA-TENG HUANG |
In-app purchases
System 911
No in-app purchases
Happy Kitty Calculator
- One-time purchase.$2.99
