# Compress a PDF - Free, No Upload, No Watermark

Page: https://hirantha.me/tools/pdf-compress
Part of: Hirantha Sandaruwan Lakshan free tools (https://hirantha.me/tools)
Updated: 2026-07-31

Shrink a scanned or image-heavy PDF by re-encoding its photos.

This is a free tool that runs in the browser: open the page to use it. File tools process files on the visitor's own device; files are never uploaded or stored. No account, sign-up, payment or watermark.

Shrink a scanned document or image-heavy PDF by re-encoding its embedded photos at a lower quality, without touching the text layer. Everything happens in your browser tab - the file is never uploaded anywhere.

Every image embedded in the PDF is found and re-encoded at your chosen quality level, then swapped in place of the original - the page layout, text, and structure are left untouched.

A PDF that's mostly text rarely has much to gain this way - structural cleanup alone only returns a percent or two, so this tool is honest when a file is already about as small as it can get, rather than reporting a trivial saving as a win.

Each image is only replaced if the re-encoded version is actually smaller - if a photo is already efficiently compressed, the original is kept rather than risking a worse result.

Quality presets at a glance:
| Preset | JPEG quality | Typical saving on a scan | Use it for |
| --- | --- | --- | --- |
| High quality | 82% | Modest | Documents that still need to look sharp when zoomed or printed |
| Balanced | 60% | Substantial | The default - a clear size drop that still reads cleanly on screen |
| Smallest file | 40% | Largest | Archives and email attachments where getting under a limit matters most |

Q: Will this make my text blurry?
A: No - only embedded images are re-encoded. Text drawn directly on the page (the normal case for anything not scanned) is untouched.

Q: Why didn't my PDF get any smaller?
A: If a PDF has no embedded images, or its images are already efficiently compressed, there's little to save - the result says so rather than reporting a negligible change as a success.

Q: Does this work on password-protected PDFs?
A: Yes - enter the password when prompted and the file is unlocked before its images are recompressed.

Q: Which images actually get recompressed?
A: Images already stored as JPEG inside the PDF. Some scanners and tools store images in ways this can't safely re-encode, in which case they're left as-is rather than risking a broken result.

Q: How much smaller will my PDF get?
A: On a scan or a photo-heavy export, commonly 60-90%. On a text-only PDF, close to nothing - and the result says so plainly rather than dressing a 1% change up as a success.

Q: Does this reduce the page dimensions?
A: No. Pages keep their size and layout exactly; only the images embedded in them are re-encoded.

Q: Can I compress a scanned document?
A: That's the case it's built for. A scan is effectively a stack of full-page photographs, which is precisely where re-encoding pays off most.

Q: Is there a page or size limit?
A: No fixed limit, but every image is decoded and re-encoded in turn, so a very long scanned document takes proportionally longer and is heavier on memory.

Sources: Portable Document Format (PDF) (https://en.wikipedia.org/wiki/PDF); JPEG - Wikipedia (https://en.wikipedia.org/wiki/JPEG)

Related tools:

- [Organise a PDF](https://hirantha.me/tools/pdf-organise.md): Delete, reorder, and rotate pages in a PDF.
- [Merge PDFs](https://hirantha.me/tools/pdf-merge.md): Combine several PDFs into one, in the order you choose.