PDF Compressor

How to use

1. Drop a PDF onto the box, or click it to pick a file.
2. Choose an image quality. 70 is a good starting point; lower it if the file is still too big.
3. Choose a maximum image size in pixels. 1600 px is plenty for reading and printing at A4.
4. Press Compress, then compare the before and after previews.
5. Download the result if you are happy with it.

Frequently asked questions

Is my PDF uploaded anywhere?

No. The file is opened, rewritten and saved entirely inside your browser tab. Nothing is sent to a server, and closing the tab leaves no copy behind.

Does the text survive? Can I still select and search it?

Yes. Only the image streams are replaced. Page content, fonts and the text layer are copied through byte for byte, so selecting, searching and copying work exactly as before. Nothing here rasterizes a page.

Nothing happened — my file barely shrank.

Then it was not images making it big. A text-only document is already close to as small as it gets, and the report will say it found no images. The other common case is a scan encoded as JPEG 2000, JBIG2 or fax, which browsers cannot re-encode; those are counted as skipped.

What quality should I pick?

70 is the usual sweet spot — a large drop in size, and on screen you would struggle to tell. Go to 50 or 40 for something that only needs to be legible, like a receipt. Stay at 85 or above for photographs where detail matters. Compare the two previews before deciding; they are rendered from the actual files.

Why does it say some images were skipped?

Because touching them would do harm. Transparency and stencil masks turn into visible halos when passed through JPEG. CMYK, indexed palettes and Lab colour do not survive a canvas, which only speaks 8-bit RGB. JPEG 2000, JBIG2 and fax encodings have no encoder in any browser. Images already small enough to be irrelevant are left as they are, and so is any image the round trip would have made bigger.

Can I get it smaller still?

Lower the maximum image size before lowering the quality — halving the pixel dimensions cuts roughly three quarters of the data and usually looks better than the same saving taken out of the quality slider. 1200 px is still sharp on screen; 800 px is fine for something that will only be read.

Does it work on password-protected PDFs?

No. An encrypted document cannot be opened without its password. Remove the protection in a reader first, then compress the result.

Guides on this topic

• Why your PDF isn't searchable You can read every word on the page, but the search box finds nothing and selecting text selects a picture. A PDF page is a set of drawing instructions, and a scanned page draws one photograph — the letters you see were never stored as letters.

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