Compress PDF

Shrink PDFs by recompressing the images inside. Nothing is uploaded.

Level
Good for sharing and email. Text stays sharp.

How to compress a PDF

  1. Add the PDFs

    Choose files or drop them on the box. You can add several at once.

  2. Pick a level

    Recommended suits email and sharing. High quality changes less. Extreme flattens pages for the smallest file.

  3. Compress and download

    Press Compress. Each row shows the size before and after, with a Download button; Download all gives a zip.

Good to know

  • Scanned documents shrink the most: a 300 dpi colour scan often drops by 70% or more at Recommended.
  • If the result would be bigger than the original, the original is kept and the row says so.
  • Images with transparency masks keep their pixel size, so they only benefit from the quality change.
  • Compression removes nothing from the text layer. Run Extreme only when you no longer need selectable text.

Questions people ask

How does it make the PDF smaller?

Most PDF weight is images. Recommended and High quality find every photo or scan inside the file, re-encode it as a JPEG at a lower quality and, when it is very large, at a smaller pixel size. Text, fonts and vector drawings are untouched, so they stay sharp and selectable.

Why did my file not get smaller?

The PDF has little or no image data, its images are already small, or they use a format the tool leaves alone such as CMYK or JBIG2 scans. Try Extreme, which flattens every page to an image, but note that text is no longer selectable afterwards.

What does Extreme do?

It renders each page as a 100 dpi JPEG and rebuilds the PDF from those images. Files get very small, but text becomes part of the picture, so it cannot be selected or searched.

Is there a file size limit?

No fixed limit. Files of a few hundred megabytes work on a normal laptop. The work runs in a background worker so the page does not freeze.

Are my PDF files uploaded?

No. Every step runs inside your browser with the pdf-lib and pdf.js libraries. Files never leave your device, there is no size or count limit beyond your computer's memory, and nothing is stored when you close the tab.