PDF Compressor

Compress PDF files with low, medium, high or maximum compression modes.

Reduce PDF file size with low, medium, high or maximum compression. Designed for scanned documents that need to fit under an upload limit.

How this compressor works

It re-renders each page as an optimised image and rebuilds the document around those. That achieves large reductions on scanned material, where the pages were images to begin with.

Diagnose before you compress

A PDF is a container, not a compression format — it packages fonts, images and drawing instructions, each stored separately. What makes yours large determines what will actually help.

SymptomLikely causeBest fix
Huge, no selectable textFull-resolution page photosThis compressor, or resize the sources
Large, text selectable, no imagesFonts embedded without subsettingRe-export from the source application
Large after many editsAccumulated revision historyAny full rewrite discards it
Large but only a few pages neededUnnecessary pagesExtract or delete pages instead

That last row is worth emphasising: removing pages is lossless with respect to the pages you keep. If a portal wants two pages of a forty-page transcript, extracting them takes the file from 8 MB to 400 KB with no quality cost at all. Try Extract PDF Pages before compressing.

Realistic targets

ContentComfortableTight but readable
Scanned text page150–300 KB80 KB
Scanned page with a photo300–600 KB150 KB
Native text page20–60 KB15 KB
Page with charts100–250 KB60 KB

How to use it

  1. Upload your PDF.
  2. Choose a compression level — start with medium.
  3. Compress and check the resulting size.
  4. Open the result and read it at 100% zoom before you submit it.

Frequently asked questions

Why can I no longer select text after compressing?

Because each page is re-rendered as an image. The characters remain visible but are no longer text objects. For scans this changes nothing; for a document from a word processor, re-export from the original instead.

How much smaller will my PDF get?

For a scanned document built from phone photos, typically 70–90%. For a PDF that is already efficiently encoded, very little — there may be nothing left to remove.

Does compressing change the page count or size?

No. Page count and page dimensions are unchanged. Only the resolution and encoding of the page content changes.

Is it safe to compress an official document?

The content is unchanged, only its encoding. Verify legibility afterwards, particularly of stamps and signatures. Some authorities require an original-quality scan, so check before compressing anything that must be certified.

Can I password-protect a PDF here?

No. Reliable client-side PDF encryption is not achievable with the libraries this site is built on, and shipping something that looks like protection but is not would be worse than shipping nothing.

Are my PDFs uploaded?

No. Compression runs entirely in your browser. The file is read from your disk, processed in the tab, and saved back to your device.

Guides that use this tool

More pdf tools · All guides · All tools