Compress PDF

The tool uses a smart hybrid approach. Text-only pages are preserved as-is — text remains selectable and searchable. Pages containing images are re-rendered at your chosen quality level to reduce file size. This keeps the output as useful as possible while still achieving meaningful compression.

Only pages that contain images are converted to image-based format. Pages with only text and vectors are copied directly, keeping text fully selectable and searchable. If your PDF is primarily text-based, most pages will be unaffected.

Results vary depending on content. Image-heavy PDFs often see 40–70% reduction. Text-only PDFs may see less reduction since they are already compact. Files that are already heavily compressed may not reduce much further.

At the default quality setting the visual difference is minimal for most documents. Lowering the quality slider further reduces file size at the cost of image sharpness. Vector graphics and diagrams may appear slightly softer than the original.

No. All compression happens locally in your browser using the Canvas API and pdf-lib. Your files never leave your device.

The default setting (around 75-80%) is a good starting point for most documents. If the compressed file is still too large, lower the quality slider. If images look blurry after compression, increase the quality. For documents you'll print or archive, keep quality above 70%. For web or email sharing, 60-70% often gives acceptable results with significant size reduction.

Adobe Acrobat uses server-side processing and requires a subscription. Coda One compresses PDFs entirely in your browser for free. For most documents, the results are comparable. For highly specialized compression needs (font subsetting, advanced image optimization), dedicated desktop software may offer more options.

Yes. Drop multiple files onto the upload area. Each file is compressed individually with the same quality setting, and you can download them all from the results screen.

This can happen with text-only PDFs or files that are already heavily compressed. When the tool detects the output is larger than the original, it falls back to a structure-rebuild approach that often still saves a few percent.

Yes. Scanned PDFs are image-heavy, so they benefit the most from compression. Expect 40-70% size reduction at medium quality. The text in scanned pages is not selectable to begin with, so no searchability is lost.

Yes. At High or Medium quality, the visual difference is minimal even when printed. For print-critical documents, use the High quality setting and verify the output before distributing.

The tool attempts to load encrypted PDFs. If successful, the compressed output will not retain the password. Use our <a href="/ai/pdf/protect">PDF Protect</a> tool to re-encrypt after compressing.

Use Medium or Low quality for email attachments. If the file is still over your email size limit, try Extreme mode or use our <a href="/ai/pdf/split">PDF Splitter</a> to send the document in parts.