PDF Compressor
Shrink a PDF by re-rendering each page as a JPEG at the quality and resolution you choose, with an optional grayscale pass and a live before/after size saving. Compressed in your browser; nothing is ever uploaded.
How it works
Each page is rendered to a canvas with Mozilla’s PDF.js, re-encoded as a JPEG at the quality and resolution you choose, then placed back into a fresh PDF with pdf-lib. Lower quality, lower DPI and grayscale all shrink the file.
Because pages are turned into images, selectable text and bookmarks are lost, this is best for scans and image-heavy PDFs, so keep your original. Everything runs in your browser; nothing is ever uploaded.
What this does
A PDF compressor shrinks a PDF by re-rendering each page as a JPEG at the quality and resolution you choose.
How to use it
- Open your PDF.
- Set quality and resolution.
- Optionally apply grayscale.
- Download the smaller file.
How it works
Pages are rendered to images and rebuilt into a new PDF in your browser, so nothing is uploaded. Because pages become images, selectable text is not carried over.
Understanding your result
Because it shrinks a PDF by re-rendering each page as an image, it cuts the size of scan-heavy or image-rich files dramatically but turns the text into a picture, so it is no longer selectable, searchable, or extractable. For a document that is mostly real text it may save little or even grow, so only reach for it when the file is genuinely image-based and the size win is worth losing the text.
Example
A scan-heavy PDF can shrink by half at lower DPI.
Sources & methodology
Last updated .
Frequently asked questions
How does the compression work?
Each page is rendered to an image and re-encoded as a JPEG at your chosen quality and DPI, then rebuilt into a new PDF. Lower quality, lower resolution and grayscale each make the file smaller.
Why did my text become unselectable?
Because pages are turned into images, the selectable text layer, bookmarks and form fields are not carried over. This approach is best for scans and image-heavy PDFs, keep your original if you need the text.
My PDF barely got smaller, why?
A PDF that is mostly crisp vector text or already-optimised images has little to gain from re-encoding. Try a lower DPI or quality, or grayscale, for documents that are mainly scans.
Is my PDF uploaded?
No. Everything is calculated locally in your browser.
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