# smark lock vs PDF Compressor

The clearest difference is in-app purchases: smark lock at none against PDF Compressor's 3. smark lock also leads on ads (none vs shown) and iOS requirement (13.0 vs 16.2). PDF Compressor's advantage is update cadence (every 3 weeks vs every 4 months). On price and device support there is nothing between them.

Both are free to download. PDF Compressor sells 3 in-app purchases, starting at $2.99 per month. smark lock asks for nothing beyond the download.

smark lock ships an update every 4 months, PDF Compressor every 3 weeks. Both last shipped on September 9, 2026.

## The numbers

| Metric | smark lock | PDF Compressor |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 4 months | **Every 3 weeks** |
| Size | 40 MB | 31 MB |
| Requires iOS | **13.0** | 16.2 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [震 王](https://appshunter.io/developer/1734329851) | [Swetha MB](https://appshunter.io/developer/599426588) |

## What reviewers say

### smark lock

[App page](https://appshunter.io/ios/app/smark-lock/id6752854176)

**Features:** macOS Compatibility

**In-app purchases:** none


### PDF Compressor

[App page](https://appshunter.io/ios/app/pdf-compressor-editor-and-tools/id6756212575)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock All Photo PDF functionality | $2.99 | per month |
| Unlock All Photo PDF functionality | $9.99 | per 6 months |
| Unlock All Photo PDF functionality | $14.99 | per year |


## Frequently asked questions

### Is smark lock free?

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

### Is PDF Compressor free?

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

### Do smark lock or PDF Compressor have ads?

PDF Compressor shows ads; smark lock does not.

### Which is updated more often, smark lock or PDF Compressor?

smark lock ships an update every 4 months, and PDF Compressor every 3 weeks. Most recently, smark lock was updated on September 9, 2026 and PDF Compressor on September 9, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*