# Operation Calculus vs KORTEK

The clearest difference is in-app purchases: Operation Calculus at none against KORTEK's 4. Operation Calculus also leads on iOS requirement (8.0 vs 15.0). On price, ads and device support there is nothing between them.

Both are free to download. KORTEK sells 4 in-app purchases, starting at $8.99 per month. Operation Calculus asks for nothing beyond the download.

## The numbers

| Metric | Operation Calculus | KORTEK |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | — | Every 3 days |
| Size | 27 MB | 16 MB |
| Requires iOS | **8.0** | 15.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [RX Labz](https://appshunter.io/developer/1223459761) | [ALEXIS SACHA ARTHUR BRASSEUR](https://appshunter.io/developer/6803713087) |

## What reviewers say

### Operation Calculus

[App page](https://appshunter.io/ios/app/operation-calculus/id1461707284)

**Features:** macOS Compatibility

**In-app purchases:** none


### KORTEK

[App page](https://appshunter.io/ios/app/kortek-remember-everything/id6803712965)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| KORTEK+ mensuel | $8.99 | per month |
| KORTEK Family | $24.99 | per month |
| KORTEK+ annuel | $89.99 | per year |
| KORTEK Family | $249.99 | per year |


## Frequently asked questions

### Is Operation Calculus free?

Operation Calculus is free to download, with no in-app purchases.

### Is KORTEK free?

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

### Do Operation Calculus or KORTEK have ads?

Neither Operation Calculus nor KORTEK shows ads.

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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.*