# Cairn vs PDF

The clearest difference is in-app purchases: PDF at none against Cairn's 3. PDF also leads on device support (3 vs 1) and iOS requirement (15.0 vs 17.0). Cairn's advantage is ads (none vs shown) and update cadence (every 2 days vs every 4 days). On price there is nothing between them.

Both are free to download. Cairn sells 3 in-app purchases, starting at $4.99 per month. PDF asks for nothing beyond the download.

Cairn ships an update every 2 days, PDF every 4 days. The most recent releases landed on October 8, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | Cairn | PDF |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | **Every 2 days** | Every 4 days |
| Size | 5 MB | 12 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [abiodun oyetomi](https://appshunter.io/developer/1895308564) | [Abdulrazaq Alonazi](https://appshunter.io/developer/6777268858) |

## What reviewers say

### Cairn

[App page](https://appshunter.io/ios/app/cairn-stop-scrolling/id6771791772)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Cairn Pro Monthly | $4.99 | per month |
| Cairn Pro Yearly | $29.99 | per year |
| Cairn Lifetime | $99.99 | one-time |


### PDF

[App page](https://appshunter.io/ios/app/pdf-scanner-and-tools/id6789006928)

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

**In-app purchases:** none


## Frequently asked questions

### Is Cairn free?

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

### Is PDF free?

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

### Do Cairn or PDF have ads?

PDF shows ads; Cairn does not.

### Which is updated more often, Cairn or PDF?

Cairn ships an update every 2 days, and PDF every 4 days. Most recently, Cairn was updated on October 8, 2026 and PDF on October 14, 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.*