PDF Compressor

Compress a PDF

1. Drag and drop a PDF file onto the upload area, or click to browse
2. Adjust the Image Quality slider — lower values produce smaller files
3. Choose a target Resolution (DPI) to downsample pages
4. Optionally enable grayscale for extra savings on color documents
5. Click Compress PDF and watch the progress bar
6. Review the before/after size comparison and click Download

How It Works

Each page of your PDF is rendered to a canvas at the resolution you select using PDF.js, then re-encoded as a JPEG image at the chosen quality. The compressed images are assembled into a brand-new PDF using pdf-lib, keeping the original page dimensions. Because pages are rasterized and images are downsampled and re-compressed, the resulting file is typically much smaller — especially for scanned documents or image-heavy PDFs.

• Image Quality — controls the JPEG compression level. Lower quality discards more image detail for a smaller file.
• Resolution (DPI) — controls how many pixels each page is rendered at. Lower DPI means fewer pixels and a smaller file.
• Grayscale — removes color information, which can noticeably shrink color-heavy pages.

Good to Know

• Compression rasterizes pages, so the output is image-based — selectable text and vector sharpness are not preserved. Keep an original copy if you need editable text.
• For already-optimized or text-only PDFs, savings may be small or the file could even grow — the tool clearly shows if that happens.
• Very large or high-page-count PDFs may take a moment to process.

Privacy & Security

• All processing happens locally in your browser using pdf-lib and PDF.js
• Your PDF files are never uploaded to any server
• No data is stored or transmitted
• Works completely offline once the page is loaded