How to compress a PDF
Almost every upload form has a size limit, and almost every scanner produces files that exceed it. The weight is nearly always in one place, and it can be taken out without ruining the document.
Open the PDF in the compression tool, choose a level, and download the lighter file. Start with the balanced level: it usually removes most of the weight with no visible difference on screen.
Compress a PDF for freeStep by step
- Add the PDF
Drop the file in. Nothing is uploaded — the compression runs on your device.
- Choose a level
Balanced is the right first try. Strong goes further and suits a document that will only ever be read on screen; light keeps the most detail.
- Compress
The images inside the file are re-encoded at a size that suits a page rather than a poster.
- Check, then download
Open the result before you send it. If the text is crisp and the photographs are good enough, you are done.
Why your PDF is heavy
Text weighs almost nothing: a hundred pages of it fit into a fraction of a megabyte. The weight is in the images, and above all in scans, where every page is a photograph stored at the scanner's resolution.
A five-page scan at 600 dots per inch is routinely larger than a two-hundred-page report. That is the file to compress, and the one where compression works best.
How far you can go before it shows
A page read on a screen, or printed at home, needs far less detail than most scanners produce. Bringing a scan down to around 150 dots per inch commonly removes three quarters of the weight and looks identical unless you zoom in.
Keep the original if the document is going to a professional printer, where the extra detail is actually used.
When compression will not help
A PDF that is already mostly text has nothing to remove; compressing it saves a few percent at best.
If such a file is still too heavy, something else is inside it — a full set of embedded fonts, or a full-page background image sitting behind the text.
Frequently asked questions
Does compressing lose quality?
Images lose some detail; text is not touched at all. At the balanced level the difference is invisible on a screen, which is where most documents are read these days.
Can I compress a PDF below a specific size?
Not exactly, because the result depends on what is inside the file. Try the balanced level, check the size, and step up to strong if you still need less.
Is my file uploaded to be compressed?
No. The whole operation happens in your browser, so a confidential report or a payslip never leaves your device.