Overview
What this tool does
Compressing a PDF reduces its file size, usually so it can be emailed, uploaded to a system with a size cap, or stored cheaply. Most PDF "bloat" comes from embedded images that were saved at higher resolution than they need to be. This compressor renders every page to a fresh canvas at a chosen DPI, re-encodes it as JPEG at a chosen quality level, and assembles a new PDF with one image per page. The output is dramatically smaller (often 50-90% smaller for image-heavy PDFs). The trade-off is that the text in the output becomes part of an image, so search and copy-paste inside the PDF no longer work. For pure text PDFs, this trade-off is rarely worth it; for scanned documents, photo-heavy reports, or anything you just need to send by email, it's the right tool. Runs entirely in your browser using pdfjs-dist (for rendering) and pdf-lib (for assembly).
How to
Use it in 3 steps
- Drop the PDF on the page (or click 'Pick PDF').
- Pick a quality level: Smallest (72 dpi, jpeg 55%), Balanced (110 dpi, jpeg 75%), or Best quality (150 dpi, jpeg 85%).
- Click 'Compress & download'. Progress shows page-by-page; large PDFs may take a minute.
- The compressed PDF is downloaded automatically when done. The size summary tells you the percentage saved.
FAQ
Frequently asked questions
▶Is my PDF uploaded?
No. Rendering and re-encoding happen in your browser. The PDF stays on your device. There is no server in the loop at any step.
▶Why does the output lose selectable text?
The compressor rasterizes each page to an image, then embeds that image in a fresh PDF. The result looks identical to the original (at the chosen quality) but the text is no longer addressable as text. If you need to keep text selectable, do not compress; consider extracting just the pages you need with the PDF Split tool instead.
▶How small will my PDF get?
Depends entirely on the input. A 50MB scanned-document PDF often shrinks to 5MB at 'Balanced'. A 1MB plain-text PDF can actually GROW because raster JPEGs are larger than vector text. The result summary will tell you.
▶What's the difference between the three modes?
Render DPI and JPEG quality. 'Smallest' (72 dpi, 55% quality) is for email attachments where size matters most. 'Balanced' (110 dpi, 75%) is for web viewing or general reduction. 'Best quality' (150 dpi, 85%) is print-ready but still smaller than the original on image-heavy PDFs.
▶Why is my compressed PDF actually LARGER?
Because the input was mostly text. Text in a PDF is vector (tiny). Rasterizing it produces JPEGs that are bigger than the original vector. If the result is larger, you don't need this tool for that file.