Compress PDF
Shrink a PDF’s file size right in your browser — great for scans.
Make a big PDF smaller
This PDF compressor is built for the most common problem: a scanned or image-heavy PDF that is simply too large to email or upload. It re-renders each page and re-encodes it as a compressed image at the quality you choose, then rebuilds the document — often cutting the file size dramatically. Everything happens in your browser with pdf.js and pdf-lib, so the file is never uploaded.
Good to know
Because pages are rebuilt from images, selectable text becomes part of the image. That is exactly what you want for scans and photo-based PDFs, but for a text document you want to keep searchable, lower the quality only as far as you need — or keep the original. Pick Low for the smallest size, High to stay close to the original look.
How to use the Compress PDF
- Choose a PDF. Select the PDF you want to make smaller; its size is shown.
- Pick a quality. Low for the smallest file, High to stay closest to the original.
- Compress. Click Compress — the PDF is rebuilt at the chosen quality in your browser.
- Download. See the size saved and download the compressed PDF.
Frequently asked questions
Is my PDF uploaded to compress it?
No. Compression runs entirely in your browser with pdf.js and pdf-lib; your PDF never leaves your device and no server sees or stores it.
What kind of PDFs compress best?
Scanned documents and image-heavy PDFs shrink the most. A PDF that is already just compact text may not get much smaller.
Will the text still be selectable afterwards?
No — because each page is rebuilt from an image, text becomes part of that image. This is ideal for scans; keep the original if you need selectable text.
What if the result is not smaller?
Some PDFs are already well optimised. The tool tells you if the rebuilt file is not smaller so you can keep your original or try a lower quality.