# OpeningBook vs Kawn

The clearest difference is ads: OpeningBook at none against Kawn's shown. On price, in-app purchases, device support and iOS requirement there is nothing between them.

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

## The numbers

| Metric | OpeningBook | Kawn |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | — | Every 2 weeks |
| Size | 4 MB | 23 MB |
| Requires iOS | **17.0** | 18.0 |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Zhenghong Peng](https://appshunter.io/developer/6797348186) | [Tariq Al-aqrabawi](https://appshunter.io/developer/1877383192) |

## What reviewers say

### OpeningBook

[App page](https://appshunter.io/ios/app/openingbook/id6805625863)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Training Mode | $3.99 | one-time |


### Kawn

[App page](https://appshunter.io/ios/app/kawn-science-encyclopedia/id6812048660)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Kawn Pro | $4.99 | one-time |


## Frequently asked questions

### Is OpeningBook free?

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

### Is Kawn free?

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

### Do OpeningBook or Kawn have ads?

Kawn shows ads; OpeningBook does not.

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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.*