PDF Slim vs UnderMB
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PDF Slim
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.
- Compress PDF files
- Adjustable quality levels
- Save compressed PDFs
- Share instantly
- View PDF details
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A smart compression app that quickly and easily reduces PDF file size! • Every Feature, No Payment Use every feature right away — no payment required. • Your Choice of Compression Quality Choose from three quality levels — Low, Medium, and High — to control how much your PDFs are compressed. The lower the quality, the smaller the file. • Detailed PDF Information Check key details at a glance, including file name, page count, file size, and creation date. • Separate Save & Instant Sharing Your original PDF stays untouched — the compressed copy is saved separately and can be shared instantly from the app.
UnderMB
Reduce the size of photos, videos, audio, and PDFs on your device. Select a target file size or use presets for common uploads like email or chat apps. Preview your compressed files before saving or sharing, with optional metadata removal.
- Compress images, videos, audio, and PDFs
- Choose target file size (KB/MB)
- Built-in presets for uploads
- Preview before saving
- Optional metadata removal
- Batch processing
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UnderMB helps you reduce photo, video, audio, and PDF file sizes to fit common upload limits. Processing happens on your device. WHAT IT DOES • Choose a target size: 500 KB, 1 MB, 2 MB, 5 MB, or a custom value • Compress images, videos, audio files, and PDFs • Preview results before saving or sharing • Built-in presets for email, visa forms, WhatsApp, and similar uploads • Optional metadata removal (EXIF/GPS, PDF info) • Batch queue for multiple files • Save to Files or share from the app PRIVACY UnderMB does not require an account. Files are processed locally and are not uploaded to UnderMB servers. GOOD FOR • Forms and portals with file size limits • Smaller email attachments • Chat apps with upload caps • Reducing file size before sharing
Screenshots
Verdict
The clearest difference is in-app purchases: UnderMB at none against PDF Slim's 1. On price, rating, ratings volume and update cadence there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. PDF Slim sells 1 one-off in-app purchase. UnderMB asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 5.0 for PDF Slim against 5.0 for UnderMB. Both are backed by a comparable volume of ratings — 1 and 1 respectively.
PDF Slim ships an update weekly, UnderMB every 11 days. The most recent releases landed on November 10, 2026 and October 31, 2026 respectively.
| Parameter | PDF Slim | UnderMB |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) | 5.0 (1 ratings) |
| Number of ratings | 1 | 1 |
| Update frequency | Weekly — better | Every 11 days |
| Ads | Yes | Yes |
| In-app purchases | Yes | No — better |
| Monetization | Ad-supported | Ad-supported |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 14 MB | 9 MB |
| Age rating | 4+ | 4+ |
| Developer | MBG Studio | CEMRE SIMSEK |
In-app purchases
PDF Slim
- Remove Ads$0.99
UnderMB
No in-app purchases
