Compress PDF Files Online — Free
Make your PDF smaller without changing how it looks. Everything runs locally in your browser — free, no signup, no uploads.
Drag & drop your PDF here
or click to browse — files stay on your device
Files never leave your deviceHow this works: we rebuild your PDF with optimized object streams. Text-based PDFs shrink well; scanned/image-heavy PDFs may barely change — that's normal, and the tool will tell you the exact result.
How to compress a PDF
- Drop a PDF into the box above (or click to browse).
- Click Compress PDF.
- Read the exact before/after result — and keep the downloaded file if it helped.
About this free PDF compressor
PDFPax's compressor reduces PDF file size entirely in your browser. Many PDFs are bloated because of inefficient internal structure: this tool rebuilds the file with optimized object streams, which often shaves off a noticeable chunk with zero change to how the document looks. Text-based documents shrink the best — reports, e-books, form letters. Honest expectations matter here: if your PDF is mostly scanned images or photos, those images are already compressed, so the file may barely change. That's normal, and the tool shows you the exact before-and-after numbers instead of guessing. Nothing is re-rendered or downsampled, so text stays perfectly sharp. No upload means no size cap and no privacy risk; your document never leaves your device. It's free, needs no account, and works offline once loaded. If a file won't shrink further, you'll know in seconds rather than waiting in a server queue.
Frequently asked questions
Why didn't my file shrink?
Text-based PDFs shrink well. If your file is mostly scanned images or photos, it's already compressed and there's nothing safe to remove — that's normal, and the tool shows you the exact before/after result instead of pretending.
Does compression reduce the quality?
No. The tool rebuilds the PDF with optimized internal object streams; it does not re-render or downsample anything, so text stays sharp and images are untouched.
Is there a file size limit?
No upload limit, because files never leave your device. Very large files only need enough free memory in your browser tab.