UsefulTab
Compress PDF
Shrink a PDF by rendering pages to compressed images.
Add a PDF to compress its file size
Drop a PDF, pick a quality preset, then click Compress. You will see the before and after size and can download the result — all in your browser, nothing uploaded.
Runs entirely in your browserCompress a PDF in your browser
This tool shrinks a PDF by rendering each page with pdf.js and re-encoding it as a compressed JPEG at a quality you choose, then rebuilding the PDF with pdf-lib. Because it rasterizes pages, it is most effective on scans and image-heavy documents — exactly the files that are usually too large. It shows the before and after size so you can see the saving, and if a setting makes the file larger it tells you. The trade-off is that text becomes part of the page image (no longer selectable), so it is a size-first compressor. Everything runs in your browser — nothing is uploaded.
Common questions
How does this compress a PDF?
It renders each page to an image and re-encodes that image as a JPEG at your chosen quality, then assembles those images into a new PDF. Lowering quality or scale makes the file smaller.
Will the text still be selectable?
No. Because pages are rasterized to images, text becomes part of the picture and is no longer selectable or searchable. This is the trade-off for strong size reduction — it works best on scans, where text already isn't selectable.
Why did my PDF get bigger, or barely change?
PDFs that are already just compressed images, or that are mostly vector text, may not shrink — re-encoding can even add bytes. The tool shows the before/after size and warns you when the result isn't smaller so you can keep the original.
Is my PDF uploaded anywhere?
No. Rendering and rebuilding both run in your browser using pdf.js and pdf-lib loaded on your device. Your document is read locally and the compressed PDF is built on your machine — nothing is sent to a server.