# RedCrab Calculator vs Calc Engine

The clearest difference is ads: Calc Engine at none against RedCrab Calculator's shown. Calc Engine also leads on update cadence (daily vs fortnightly). RedCrab Calculator's advantage is iOS requirement (15.6 vs 18). On price, in-app purchases and device support there is nothing between them.

Both are free to download. RedCrab Calculator sells 1 one-off in-app purchase and Calc Engine sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

RedCrab Calculator ships an update fortnightly, Calc Engine daily. The most recent releases landed on August 30, 2026 and August 31, 2026 respectively.

## The numbers

| Metric | RedCrab Calculator | Calc Engine |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (4 ratings)](https://appshunter.io/ios/app/calc-engine/id1061766849/reviews)** |
| Number of ratings | — | **4** |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | Fortnightly | **Daily** |
| Monetization | — | Free |
| Size | 4 MB | 17 MB |
| Requires iOS | **15.6** | 18 |
| Devices | iPhone, iPad, iPod | **iPhone, iPad, Mac, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [少泽 梁](https://appshunter.io/developer/897112791) | [VersaEdge Software, LLC](https://appshunter.io/developer/301294952) |

## What reviewers say

### RedCrab Calculator

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

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

**In-app purchases (1)**

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


### Calc Engine

[App page](https://appshunter.io/ios/app/calc-engine/id1061766849)

A highly customizable calculator with advanced features like graphing, equation solving, and unit conversion. Design your own keyboards and functions to streamline your workflow across Apple devices.

**Highlights:** Customizable keyboard layouts, User-defined functions and constants, Live equation graphing, Equation solving, Extensive unit conversions, Programmer mode (hex, binary, octal), Cross-device syncing

**Features:** Family Sharing, Apple Watch app

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Calc Engine+ | $9.99 | one-time |


## Frequently asked questions

### Is RedCrab Calculator free?

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

### Is Calc Engine free?

Calc Engine is free to download, with in-app purchases available.

### Do RedCrab Calculator or Calc Engine have ads?

RedCrab Calculator shows ads; Calc Engine does not.

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

RedCrab Calculator ships an update fortnightly, and Calc Engine daily. Most recently, RedCrab Calculator was updated on August 30, 2026 and Calc Engine on August 31, 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.*