How to compress a PDF
- Add one or more PDFs. Drop them on the box, paste them with Ctrl+V, or press Select PDF files.
- Pick a level. Recommended suits most files. Choose Less compression for photos you may print, or Extreme when the file only has to be small, for example for an upload form with a size limit.
- Press Compress PDF. You see the old size, the new size and the percentage saved for every file.
- Download the smaller PDF, or a .zip when you compressed several files.
What gets smaller, and what stays the same
Most large PDFs are large because of photos: phone pictures, scanned pages and product shots are often saved at a much higher resolution than a screen or a printer needs. This tool measures how big each photo is shown on its page, scales it down to a sensible resolution and saves it again as a JPEG:
| Level | Photos keep up to | JPEG quality |
|---|---|---|
| Less compression | 200 DPI | high (82%) |
| Recommended | 144 DPI | good (72%) |
| Extreme | 96 DPI | low (50%) |
A new image only replaces the old one when it is clearly smaller, so photos that are already compact are left alone. Images that are drawn small on the page lose the most pixels, because nobody can see them anyway.
Text, fonts, lines, charts and other drawings are not changed at all. Text stays sharp at any zoom level, and you can still select, search and copy it. The tool also does some lossless tidying: it compresses parts of the file that were stored without compression, drops leftovers that nothing in the file uses any more, and packs the file structure more tightly.
When a PDF can't be made smaller
A PDF that is mostly text, such as a contract or a report exported from a word processor, has no large photos to shrink. Its size comes from text and fonts, and those are kept exactly as they are. In that case the tool tells you that the file can't be made much smaller and leaves it unchanged, instead of handing you a "compressed" file that is barely different. The same happens when the photos in a file were already compressed well.
Some image types are also kept as they are: CMYK images made for professional printing, images with special color settings, and black-and-white fax-style scans, which are usually small already.
Private and fast
Your files are processed in your browser and never uploaded. A 20 MB PDF full of photos usually takes a second or two, and each file can be up to 200 MB. A password-protected PDF has to be opened and saved without its password first.
Frequently asked questions
Will compressing make my PDF blurry?
Text and drawings stay exactly as sharp as before. Photos lose some detail: with Recommended this is hard to see on screen, with Extreme it shows when you zoom in.
Why did my PDF only shrink a little?
Its size comes mostly from text, fonts or images that were already compressed. The tool only shrinks photos that are larger than they need to be.
Can I compress several PDFs at once?
Yes. Add them all, press Compress PDF, and you get every smaller file in one .zip, with the saving shown for each file.
Is the original file changed?
No. Your original stays as it is on your device. The tool makes a new copy with "-compressed" added to the name.
This tool works in your browser: your files are processed on your device and are never uploaded. Check the result before you share it or delete the original.