# RedCrab Calculator vs + Simple Calc

The clearest difference is in-app purchases: + Simple Calc at none against RedCrab Calculator's 1. + Simple Calc also leads on ads (none vs shown) and update cadence (every 5 days vs fortnightly). RedCrab Calculator's advantage is device support (3 vs 1). On price, review sentiment and iOS requirement there is nothing between them.

Both are free to download. RedCrab Calculator sells 1 one-off in-app purchase. + Simple Calc asks for nothing beyond the download.

RedCrab Calculator ships an update fortnightly, + Simple Calc every 5 days. The most recent releases landed on October 24, 2026 and October 19, 2026 respectively.

## The numbers

| Metric | RedCrab Calculator | + Simple Calc |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/plus-simple-calc/id6448763641/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Fortnightly | **Every 5 days** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 5 MB | 4 MB |
| Requires iOS | **15.6** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [少泽 梁](https://appshunter.io/developer/897112791) | [Alejandro de la Rosa Cortes](https://appshunter.io/developer/1506520491) |

## 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 |


### + Simple Calc

[App page](https://appshunter.io/ios/app/plus-simple-calc/id6448763641)

Perform calculations with a standard calculator that offers extensive customization. Choose from 17 color themes and custom icons, plus enjoy light and dark mode support.

**Highlights:** Standard calculator functionality, Light and dark mode, 17 color themes, Custom icons, iPhone support

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is RedCrab Calculator free?

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

### Is + Simple Calc free?

+ Simple Calc is free to download, with no in-app purchases.

### Do RedCrab Calculator or + Simple Calc have ads?

RedCrab Calculator shows ads; + Simple Calc does not.

### Which is updated more often, RedCrab Calculator or + Simple Calc?

RedCrab Calculator ships an update fortnightly, and + Simple Calc every 5 days. Most recently, RedCrab Calculator was updated on October 24, 2026 and + Simple Calc on October 19, 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.*