Compresses embedded JPEG images and repacks the document for the smallest output on scanned PDFs.
Drop a PDF here to compress
Smart mode recompresses embedded JPEGs in a Web Worker — text and vectors stay intact.
Compression runs entirely in a Web Worker on your device —
your PDF is never uploaded.
Compress PDF helps you compresses embedded jpeg images and repacks the document for the smallest output on scanned pdfs. It is commonly used by professionals, students, general users for compress pdf, reduce pdf size, pdf compressor online.
How to Compress a PDF
Reduce the size of reports, scans, or image-heavy documents without sending anything to a server.
How It Works
- **Pick one PDF** — Drop or select a single file
- **Choose a mode**
- - **Smart (recommended)** — Walks every image XObject, finds embedded JPEGs, and re-encodes each one at the chosen quality with an optional downscale. Text, fonts, and vector graphics are untouched.
- - **Aggressive (rasterize)** — Uses PDF.js to render every page to a JPEG, then rebuilds the PDF from those images. Smallest output, but text becomes non-selectable and forms/signatures/accessibility tags are lost.
- **Choose a quality preset** — Maximum compression, Balanced, or High quality. This controls JPEG quality (0.5/0.72/0.85) and an image dimension cap (1200/1800/2400 px on the long edge).
- **Optional privacy** — Strip title, author, creator, and producer metadata.
- **Compress** — A Web Worker does all the work; your file bytes are transferred (not copied) for memory efficiency.
- **Download** — Save the compressed PDF, or keep the original if the output ended up larger.
Security & Privacy
Everything runs in your browser. The PDF buffer is transferred to a dedicated Web Worker and never leaves your machine.
Limits & Caveats
- **Already-optimized PDFs** may not shrink further in Smart mode — you'll be told and offered the original file back.
- **Encrypted PDFs** are loaded with `ignoreEncryption`, but if the image streams themselves are encrypted, recompression may be skipped.
- **JBIG2 / JPEG2000 / CCITTFax monochrome scans** are not supported in Smart mode. Use Aggressive for those.
- **Forms, annotations, digital signatures** are preserved by Smart mode but destroyed by Aggressive mode.
- Very large scans use a lot of memory; close other heavy tabs if you hit browser limits.