Compress PDF Online Free
Reduce your PDF file size instantly in your browser — free, no sign-up, no watermark and no upload to any server. Powered by real Ghostscript compression running locally on your device.
Drag & drop your PDF here
or click to browse
Multiple PDFs supported · No sign-up required · Runs entirely in your browser
Compression complete
100% Private — No Upload
All compression happens entirely inside your browser using Ghostscript WebAssembly. Your file is never sent to any server, never stored and never seen by anyone else.
Real Image Recompression
Unlike basic PDF tools, this uses the full Ghostscript engine which actually recompresses embedded images inside your PDF — the same way professional desktop software does it.
Three Compression Levels
Light keeps quality at 300dpi for printing. Medium at 150dpi is ideal for email and sharing. Strong at 72dpi gives the smallest possible file for web or storage.
How to Compress a PDF Online — 4 Simple Steps
Reducing your PDF file size takes under a minute with FreeConverto. No account, no watermarks — your file never leaves your device. Also try our free PDF merger to combine multiple PDFs, or our PDF splitter to remove pages before compressing.
Upload Your PDF
Drag and drop your PDF onto the upload area or click to browse. Multiple PDFs supported — all will be compressed and delivered as a ZIP.
Choose a Level
Pick Light for near-lossless, Medium for the best balance of size and quality, or Strong for the maximum possible compression.
Compress PDF
Click Compress PDF. Ghostscript runs entirely in your browser — no upload needed. Large files may take 10–30 seconds depending on your device.
Download Free
Download your compressed PDF instantly. No watermark, no sign-up and no upload to any server ever required.
Tips to Get the Best PDF Compression Results
Image-heavy PDFs compress the most
PDFs with large embedded images benefit most — Ghostscript recompresses each image individually. Try Strong for presentations, scanned documents and brochures.
Text-only PDFs may not shrink much
PDFs containing only text and vector graphics are already highly efficient. Ghostscript will still optimise them but gains will be smaller — this is normal.
Large files take a moment
Because Ghostscript recompresses every embedded image, a large 50MB file may take 20–40 seconds. A progress bar keeps you updated throughout.
Remove unnecessary pages first
Use our free PDF splitter to remove pages you don't need before compressing. Fewer pages always means a smaller file to start with.
Scanned PDFs compress dramatically
Scanned documents are essentially large images. Strong compression can reduce a 20MB scanned PDF to under 2MB while keeping text perfectly readable.
Need under 10MB for email?
Most email providers limit attachments to 10–25MB. Run Medium or Strong compression first. If still too large, split it with our PDF splitter and send in parts.
Frequently Asked Questions
How do I compress a PDF online for free?
Upload your PDF, choose a compression level — light, medium or strong — then click Compress PDF. Ghostscript processes your file entirely in your browser with no upload to any server. Your reduced file downloads instantly, free with no watermark and no sign-up required.
How much will my PDF file size reduce?
Results depend on content. Image-heavy PDFs — presentations, scanned documents, brochures — typically shrink 30–70% on Medium or Strong. Text-only PDFs may see 5–20% reduction since the content is already efficiently encoded. The tool always shows exact before and after sizes.
Will compressing the PDF reduce its quality?
Light targets 300dpi — virtually no visible quality change, suitable for printing. Medium targets 150dpi — excellent for screen reading and email. Strong targets 72dpi — maximum reduction, images will appear smaller on screen but text always remains sharp and fully readable.
Why is my PDF not getting much smaller?
If your PDF contains mainly text and vector graphics, Ghostscript will still apply all optimisations but gains will be modest. Try removing unneeded pages first with our PDF splitter, then compress again.
Will my PDF be uploaded to a server?
No — your file never leaves your device. All compression is done entirely in your browser using Ghostscript compiled to WebAssembly. No data is sent to FreeConverto servers at any point. Your document stays completely private.
What other free PDF tools does FreeConverto offer?
FreeConverto offers a full suite of free PDF tools including a PDF merger, PDF splitter, PDF rotator, PDF to JPG converter and PDF watermark tool. All are 100% free with no sign-up. Also explore our free image tools.