PDF Basics

How to Compress a PDF Without Losing Quality

Compression is usually forced on you by a limit: an upload form that caps files at 2 MB, or an email that will not send. Knowing which kind of PDF you have tells you straight away how much room there is to manoeuvre.

5 min readUpdated 14 September 2026Dockeazy editorial

The short answer

Upload the PDF, pick a compression level, and download the smaller file. How much you save depends almost entirely on whether the PDF contains scanned images or real text — images compress a lot, text barely at all.

Compress PDF

Shrink file size while keeping the best quality.

Open Compress PDF

Step by step

1Check what kind of PDF you haveTry selecting text in the document. If you can highlight words, it is a text PDF and already small. If nothing selects, it is a scan made of images — that is where the size is.
2Upload the file and choose a levelA lighter level keeps more detail and saves less. A stronger level saves more and softens images. Text stays sharp either way.
3Compare the result before and afterThe tool reports both sizes. If the saving is under one percent, the file was already efficient and compressing again will not help.
4Check the pages you actually care aboutLook at anything containing small print, a stamp, or a signature. Those are the first things to degrade at stronger settings.

Why some PDFs refuse to get smaller

A PDF exported from Word or Google Docs is mostly instructions: draw this text, in this font, at this position. That is already extremely compact, so there is very little to remove.

A scanned PDF is a stack of photographs. A single colour page scanned at 600 DPI can easily be several megabytes on its own, which is why a ten-page scan dwarfs a hundred-page text document.

If you compress a text PDF and save almost nothing, the tool is not failing. There was simply nothing left to take out.

Getting under a specific limit

Government and university portals often demand something quite specific, like under 100 KB or under 2 MB. For a scan, start with a stronger compression level rather than working up from the lightest.

If a scan still will not fit, the real problem is usually resolution. Rescanning at 200–300 DPI in greyscale produces a dramatically smaller file than compressing a 600 DPI colour scan after the fact.

Removing pages you do not need is the other lever people forget. Four pages instead of twelve is a two-thirds saving before compression even runs.

What compression does not touch

Text remains text. Compression does not flatten a document into images, so it stays searchable and selectable afterwards.

Page dimensions, orientation and page count are unchanged. If you need fewer pages or a different order, that is a separate job.

Frequently asked questions

How much smaller will my PDF get?

Scanned documents commonly drop by half or more. Text-based PDFs often change very little, because they are already compact.

Will the text become blurry?

No. Text is stored as instructions rather than pixels, so it stays crisp. Compression affects embedded images.

Can I compress a PDF more than once?

You can, but the second pass usually saves very little and costs more quality. One pass at the right level is better.

My file is still too big. What now?

Rescan at a lower DPI in greyscale, or split the document and send the relevant section on its own.