PDF Compressor
Reduce PDF file size by stripping comments, metadata, and redundant whitespace — all in your browser, no upload required.
📄
Drag & drop a PDF here
or click to browse — max 20 MB
💡 What this tool compresses
- PDF comments and unused whitespace
- XMP metadata packets
- Optional document info entries (Author, Subject, Keywords…)
Note: Binary image streams are not re-encoded. For image-heavy PDFs, the reduction may be minimal. All processing happens locally in your browser.
Frequently Asked Questions
How does PDF compression work?
PDF compression reduces file size by optimizing image quality, removing embedded fonts that aren't needed, and stripping metadata. Our tool provides lossless compression of PDF structure without degrading embedded images.
Is my PDF uploaded to a server?
No. PDF processing happens in your browser using JavaScript. Your file never leaves your device.
How much can I reduce a PDF's size?
For PDFs with large embedded images, compression can reduce size by 30–80%. For text-only PDFs, the reduction is typically 5–20%.
Will compression affect PDF quality?
The tool removes unnecessary metadata and optimizes structure without changing text or layout. Image quality is preserved with our lossless compression option.
What Makes a PDF Large?
A PDF file is a container of objects — images, fonts, text streams, metadata, and binary data. The largest contributors to PDF file size are:
- Embedded images — scanned pages, photos, and screenshots saved at print resolution (300 DPI) far exceed screen resolution needs (72–96 DPI).
- Embedded fonts — some PDFs embed entire font files including glyphs that are never used in the document.
- Metadata and annotations — hidden author information, revision history, and XMP metadata add overhead.
- Uncompressed streams — older PDFs may store content streams without Flate (Deflate/zlib) compression.
Compression Techniques
| Technique | Effect | Lossy? |
|---|---|---|
| Remove metadata | Strips author, keywords, creation date | No |
| Re-compress streams | Applies zlib to uncompressed content streams | No |
| Subset embedded fonts | Keep only glyphs actually used | No |
| Downsample images | Reduce image DPI from 300 to 72/150 | Yes |
| JPEG re-encode images | Re-compress images at lower quality | Yes |
| Convert to Grayscale | Remove colour data from images | Yes |
Best Practices for Small PDFs
- Export at screen resolution — when saving from Word or Google Docs, choose “Optimize for online/email” rather than “print”.
- Use vector graphics — SVG and vector diagrams are scalable and far smaller than raster screenshots.
- Avoid scanning as images — scan to PDF with OCR so the content is text, not a JPEG image per page.
- Check PDF/A requirements — PDF/A for archiving requires embedded fonts; some compressions (removing fonts) are not allowed in PDF/A files.