# PDF Slim vs UnderLimit

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

Both are free to download. UnderLimit sells 1 one-off in-app purchase. PDF Slim asks for nothing beyond the download.

PDF Slim ships an update weekly, UnderLimit every 2 days. The most recent releases landed on October 10, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | PDF Slim | UnderLimit |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/pdf-slim-reduce-pdf-size/id6787603119/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Weekly | **Every 2 days** |
| Monetization | Ad-supported | — |
| Size | 4 MB | 4 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [MBG Studio](https://appshunter.io/developer/1401126212) | [ALESSANDRO VINCENZO DEL BALZO](https://appshunter.io/developer/6813135046) |

## What reviewers say

### PDF Slim

[App page](https://appshunter.io/ios/app/pdf-slim-reduce-pdf-size/id6787603119)

Reduce the size of your PDF files with adjustable quality settings. Save or share compressed documents directly from the application. Access detailed information about each PDF.

**Highlights:** Compress PDF files, Adjustable quality levels, Save compressed PDFs, Share instantly, View PDF details

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

**In-app purchases:** none


### UnderLimit

[App page](https://appshunter.io/ios/app/underlimit-pdf-compressor/id6813135044)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| UnderLimit Unlimited | $2.99 | one-time |


## Frequently asked questions

### Is PDF Slim free?

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

### Is UnderLimit free?

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

### Do PDF Slim or UnderLimit have ads?

Neither PDF Slim nor UnderLimit shows ads.

### Which is updated more often, PDF Slim or UnderLimit?

PDF Slim ships an update weekly, and UnderLimit every 2 days. Most recently, PDF Slim was updated on October 10, 2026 and UnderLimit 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.*