Calendar vs Square Root Pro
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Calendar
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Supported Languages: German and English With this app you can train your ability to calculate a weekday for any given date. It offers a great variety of training methods. This app also gives you an overview of my method/simplification on how the algorithm works and how you can calculate it in your head.
Square Root Pro
This app helps you mentally calculate square roots to two decimal places. It supports multiple languages and an internationalized numeric system for global users.
- Mental square root calculation
- Accuracy to 2 decimal places
- Multilingual support (English, Spanish, French, German, Chinese)
- Internationalized numeric system
- Educational tool for math and science
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Square roots are often found in math & science and quick calculation is sometimes necessary in order to tackle common questions. This app teaches you mentally calculate square roots to reasonable accuracy (2 decimal places). Switch easily between English, Spanish, French, German & Chinese (Mandarin). Fully internationalized numeric system.
Screenshots
Verdict
The clearest difference is price: Square Root Pro at Free against Calendar's $31.99. Square Root Pro also leads on update cadence (every 8 months vs every 31 months). Calendar's advantage is ads (none vs shown) and iOS requirement (15.6 vs 17.6). On in-app purchases 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
Square Root Pro is free to download; Calendar costs $31.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Calendar ships an update every 31 months, Square Root Pro every 8 months. The most recent releases landed on October 18, 2026 and October 8, 2026 respectively.
| Parameter | Calendar | Square Root Pro |
|---|---|---|
| Price | $31.99 | Free — better |
| Rating | — | 5.0 (3 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 3 — better |
| Update frequency | Every 31 months | Every 8 months — better |
| Ads | No — better | Yes |
| In-app purchases | No | No |
| Monetization | — | Ad-supported |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.6 — better | 17.6 |
| Further details — not scored | ||
| Size | 1 MB | 30 MB |
| Age rating | 4+ | 4+ |
| Developer | Martin Eisele | Thomas Bradshaw |
In-app purchases
Calendar
No in-app purchases
Square Root Pro
No in-app purchases
Questions
Is Calendar free?
Is Square Root Pro free?
Do Calendar or Square Root Pro have ads?
Which is updated more often, Calendar or Square Root Pro?
Other comparisons
