Compress PDF Files
Shrink a PDF's file size by rebuilding its internal structure and removing redundant overhead — free, in your browser, with no quality loss.
How to compress a PDF
One file in, one smaller file out.
Add your PDF
Drop in the file you want to shrink
We rebuild it
Internal structure is optimized automatically — nothing to configure
Download
Get your smaller PDF, same visual quality
What this tool actually does
Being straightforward about this matters more than a big marketing number: FileSeb's Compress PDF tool rebuilds your file's internal structure — cleaning up redundant objects and reorganizing how the file is stored — rather than recompressing or downscaling the images inside it. That means it's completely safe for text-heavy documents, contracts, and reports, with zero visual quality loss, but the size reduction will be modest on a PDF that's large mainly because of high-resolution embedded photos.
If your PDF is a scan or photo-heavy document and you need a much smaller file, your best result usually comes from lowering image resolution before it becomes a PDF in the first place — for example, using the Image Compressor on your source photos, or the PDF Scanner tool, before converting.
How to compress a PDF, step by step
- Add your PDF. Any PDF under your device's memory limit works — scanned documents included.
- Review the before/after sizes. After compression the app reports both file sizes so you can see the real saving, not a guess.
- Download the smaller file. If the saving is not enough, compress the images inside the document first (Image Compressor) and rebuild, or export pages selectively.
Limits worth knowing
This tool rewrites the PDF's internal structure — merging duplicate objects and packing data into compressed streams — without re-encoding your images, so visual quality is untouched. PDFs that are already optimized, or documents made of one large scanned image, have less structural fat to trim and will shrink less. That is an honest limit of lossless compression, not a failure.
Privacy
Compression happens entirely in this tab. Your document is never uploaded anywhere.
Questions about compressing PDFs
It depends on the file. This tool rebuilds the PDF's internal structure and removes redundant overhead, which typically gives a modest, reliable reduction. It does not recompress or downscale embedded images, so a PDF that's large mainly because of high-resolution images won't shrink dramatically.
No. This tool only optimizes the file's internal structure — it doesn't re-encode or downsample images, so visual quality is unaffected.
Yes, it's safe to run, but because scanned PDFs are usually large due to embedded photo-like page images rather than file overhead, the size reduction will likely be smaller than on a text-heavy PDF.
No. Compression happens entirely inside your browser using JavaScript. Your PDF is never sent to a server.
→ Read the full guide: How to Reduce a PDF's File Size (every method explained)
Related PDF tools
- Merge PDF — combine multiple PDFs into one
- Split PDF — break one PDF into a file per page
- PDF to Word — convert a PDF into an editable .docx