# Smart PDF Compressor vs PDF Under

The clearest difference is in-app purchases: Smart PDF Compressor at none against PDF Under's 3. Smart PDF Compressor also leads on update cadence (every 9 days vs every 3 weeks). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. PDF Under sells 3 in-app purchases, starting at $1.99 per 7 days. Smart PDF Compressor asks for nothing beyond the download.

Smart PDF Compressor ships an update every 9 days, PDF Under every 3 weeks. The most recent releases landed on October 31, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Smart PDF Compressor | PDF Under |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 9 days** | Every 3 weeks |
| Size | 4 MB | 3 MB |
| Requires iOS | 18.0 | **17.6** |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Quan Dang](https://appshunter.io/developer/1868401962) | [Emre KABOGLU](https://appshunter.io/developer/1892627286) |

## What reviewers say

### Smart PDF Compressor

[App page](https://appshunter.io/ios/app/smart-pdf-compressor-reduce/id6757997785)

**Features:** macOS Compatibility

**In-app purchases:** none


### PDF Under

[App page](https://appshunter.io/ios/app/pdf-under-pdf-compressor/id6804278677)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| PDF Under Weekly | $1.99 | per 7 days |
| PDF Under Yearly | $13.99 | per year |
| PDF Under Lifetime | $19.99 | one-time |


## Frequently asked questions

### Is Smart PDF Compressor free?

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

### Is PDF Under free?

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

### Do Smart PDF Compressor or PDF Under have ads?

Neither Smart PDF Compressor nor PDF Under shows ads.

### Which is updated more often, Smart PDF Compressor or PDF Under?

Smart PDF Compressor ships an update every 9 days, and PDF Under every 3 weeks. Most recently, Smart PDF Compressor was updated on October 31, 2026 and PDF Under on October 25, 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.*