A 50 MB PDF is a problem. Most email clients cap attachments at 25 MB. Many file upload forms reject anything over 10 MB. And even when size limits are not an issue, large PDFs are slow to open on mobile. Compression fixes all of this.
Why are PDFs so large?
The culprits are almost always embedded images. When you export a document to PDF, images are often embedded at full resolution — even a scan of a printed page can balloon to 5-10 MB per page. Fonts and metadata add more bulk.
How PDF compression works
Good compression tools (including FormatNest) use Ghostscript, which:
- Resamples embedded images to 150 DPI (screen-quality)
- Re-compresses images using JPEG
- Removes embedded metadata and revision history
- Strips unused font subsets
How much will it shrink?
- Scanned documents — often 70-90% smaller. A 30 MB scan can become 3 MB.
- Documents with photos — 40-70% smaller.
- Text-only PDFs — 10-30% smaller.
How to compress a PDF on FormatNest
- Open PDF Compress.
- Upload your PDF.
- Click Compress.
- Download the smaller version.
The compressed PDF is processed on FormatNest's servers and deleted within an hour — nothing is stored permanently.
Will quality suffer?
For screen viewing and email, no — the difference is invisible. For print, downsampling images to 150 DPI can soften fine detail. Use the original file for printing and the compressed version only for sharing.
Tip: split before compressing
If you only need to share certain pages, split the PDF first to extract the relevant section, then compress that smaller file.