# RedCrab Calculator vs Notelys

The clearest difference is price: RedCrab Calculator at Free against Notelys's $0.29. RedCrab Calculator also leads on iOS requirement (15.6 vs 17.0). Notelys's advantage is in-app purchases (none vs 1) and update cadence (every 4 days vs fortnightly). On ads and device support there is nothing between them.

RedCrab Calculator is free to download; Notelys costs $0.29 up front. RedCrab Calculator sells 1 one-off in-app purchase. Notelys asks for nothing beyond the download.

RedCrab Calculator ships an update fortnightly, Notelys every 4 days. Both last shipped on October 24, 2026.

## The numbers

| Metric | RedCrab Calculator | Notelys |
| --- | --- | --- |
| Price | **Free** | $0.29 |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Fortnightly | **Every 4 days** |
| Monetization | Free with in-app purchases | — |
| Size | 5 MB | 5 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [少泽 梁](https://appshunter.io/developer/897112791) | [Kerem Gonlkrmaz](https://appshunter.io/developer/1882973074) |

## What reviewers say

### RedCrab Calculator

[App page](https://appshunter.io/ios/app/redcrab-calculator/id947845140)

This powerful scientific calculator offers a modern UI and robust engine for users of all levels. It handles basic arithmetic to complex engineering equations with smart expression parsing and a high-precision display. Enjoy a seamless calculation experience with features like history recall and dark mode.

**Highlights:** Basic & Advanced Calculations, Smart Expression Parsing, Calculation History & Reuse, High-Precision Display, Dark Mode & Modern UI, VIP Ad-Free Experience

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 终身会员 | $1.99 | one-time |


### Notelys

[App page](https://appshunter.io/ios/app/notelys-smart-voice-notes/id6760238553)

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is RedCrab Calculator free?

RedCrab Calculator is free to download, with in-app purchases available.

### Is Notelys free?

Notelys costs $0.29, with no in-app purchases.

### Do RedCrab Calculator or Notelys have ads?

Both RedCrab Calculator and Notelys show ads.

### Which is updated more often, RedCrab Calculator or Notelys?

RedCrab Calculator ships an update fortnightly, and Notelys every 4 days. Most recently, RedCrab Calculator was updated on October 24, 2026 and Notelys on October 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*