Compress PDF

The same 10-page document can be 200KB or 200MB depending on how it was made. The usual culprits:

• Scans at high resolution. 600 DPI scans look great but balloon to 5–10MB per page.
• Photos embedded at full size. A modern phone photo is 4–8MB raw. Drop a few of those into a PDF and you're at 50MB fast.
• PowerPoint exports. Slides with full-bleed images print to PDF without any compression.
• Office "save as PDF" with embedded fonts and metadata bloat.

The fix: re-encode the embedded images with sensible JPEG quality and discard redundant metadata. That's what compression tools do.

1. Open Compress PDF.
2. Drop your file or click to browse.
3. Pick a compression level: Light, Medium, or Strong.
4. Click Compress. The reduced file downloads automatically; the size before/after and percent saved is shown.

Compression runs in your browser via pdfjs-dist (for rendering each page) and pdf-lib (for rebuilding the file). On a 2022 MacBook Air, a 50-page 30MB PDF compresses in about 8 seconds.

If you're not sure, try Medium first and check the output. If it's still too big, run again at Strong.

This tool re-renders each page as a JPEG and rebuilds the PDF with those images. The trade-off is real and worth knowing:

• Searchable text becomes images. The output is a flat image PDF — you can't select text or search it. If you need searchable output, skip compression and use a smaller-scale tool like Acrobat's Save As Reduced Size PDF, which only compresses images and leaves text streams alone.
• Vector content (charts, diagrams) gets rasterized. They'll still look identical at the chosen DPI but lose infinite-zoom quality.
• Form fields get flattened. Don't compress a form you still need someone to fill in.

For pure-text PDFs (a Word export, say), compression won't help much — text is already small. Compression earns its keep on image-heavy and scanned PDFs.

Real numbers from typical inputs:

• 10-page scanned contract (40MB) → Medium → ~6MB. Readable at 100% zoom; perfect for email.
• 50-page expense receipts batch (120MB) → Strong → ~12MB. Receipt text still legible; passes corporate email filters.
• 200-page travel-photo album PDF (800MB) → Strong → ~60MB. Photos still look fine on a phone; uploadable to most cloud drives.
• 20-page Word-exported report (2MB) → Medium → ~1.8MB. Negligible savings because text is already tiny; not worth compressing.

If you need text to stay searchable, Acrobat or Ghostscript are better picks. For a one-off file with image-heavy content, the browser tool is faster and free.

• File got bigger after compression. Your source PDF was already heavily optimized (text-only Office export). Compression can't help. Skip it.
• Output looks blurry. You chose Strong and the source had tiny text. Try Medium or Light.
• Compression is very slow. Large PDFs (200+ pages) take time because each page is rendered then re-encoded. Close other tabs to give the browser more RAM.
• Need to keep text searchable? This tool's approach won't preserve searchability. Use Acrobat's Reduce File Size, or run PDF OCR on the compressed output afterwards (when that tool ships).

People compress PDFs they're about to email — contracts, tax forms, medical records. Most online compressors upload your file to their server, run the compression there, and email you a link. That puts your sensitive document on someone else's disk, even briefly. SwissArmyPDF runs the entire compression locally in your browser. There's no server in the loop. Open DevTools, Network tab, and verify yourself: no outbound traffic.

• Merge PDF — combine your compressed files with others.
• Sign PDF — add a signature before sending.
• Watermark PDF — brand the compressed copy as draft or confidential.
• PDF to JPG — if you only need a few pages as images instead of a PDF.