Optimize PDF
Compress a PDF, keep the text sharp
This tool makes a PDF smaller by saving the photos and scans inside it at a lower resolution and quality, in your browser. Text, fonts and drawings stay exactly as they are. Pick a level, press Compress, and compare the sizes before you download.
or drop files here, or paste with Ctrl/Cmd+V
PDF · up to 50 files · 100 MB each
No file to hand?
Your files stay on your device. Nothing is uploaded. Check it yourself
How to use Compress PDF
Add your PDFs
Drop one or more PDFs on the box, or click to browse. Up to 50 files of 100 MB each.
Pick a level
Light, Recommended or Strong. Recommended suits most documents.
Compress and download
Press Compress. You see the old and the new size before you save; several files can be saved as one zip.
What Compress PDF changes, and what it leaves alone
Most of the weight of a large PDF is usually pictures: scanned pages, photos from a phone, screenshots. PlumPDF looks at each image, works out how large it is drawn on the page, and if it holds more detail than the chosen level needs, scales it down and saves it as a JPEG. A photo printed 10 cm wide does not need 4000 pixels across.
An image is only swapped when the new version is clearly smaller; otherwise its original data stays. Images with transparency, CMYK colour, JPEG 2000 or JBIG2 data are always left as they are, so nothing changes colour or loses its see-through parts.
Everything else is copied untouched: text, embedded fonts, vector drawings, links, bookmarks and form fields. The file is then saved with its objects packed together, and leftovers from earlier edits that nothing uses any more are dropped.
The greyscale option turns photos and scans grey. Text and drawings keep their colours.
Questions about Compress PDF
Can I compress a PDF to an exact size, like 1 MB or 200 KB?
Yes. Choose "Choose a size" and type the largest size in KB. The photos and scans inside are made smaller step by step until the PDF fits, keeping the best quality that does. If the text and fonts alone are bigger than your limit, you get the smallest version possible and are told so.
How do I reduce the size of a PDF?
Add the PDF above, keep the Recommended level and press Compress PDF. PlumPDF saves the images inside the file again at up to 150 DPI and shows you the new size before you download it. For an even smaller file, choose Strong.
How much smaller will my PDF get?
It depends on what the file is made of. Scans and PDFs full of phone photos often shrink by half or more, because their images hold far more detail than a screen or a printer needs. A PDF that is mostly text has little to remove. Some images are always left alone because changing them could go wrong: images with transparent parts, CMYK print images, JPEG 2000 and fax-style black-and-white scans (JBIG2, CCITT) and very small images. If the result is not smaller, PlumPDF tells you and you keep the original.
Will the text become blurry?
No. Text, fonts, lines and shapes are copied as they are, so they stay sharp at any zoom and remain selectable. Only pictures are saved again. In a scanned document the whole page is a picture, so there the text is part of the image and gets a little softer at the Strong level.
What do Light, Recommended and Strong mean?
They set the resolution and JPEG quality for images. Light keeps up to 200 DPI at quality 85, Recommended up to 150 DPI at quality 72, and Strong up to 110 DPI at quality 60. Resolution is measured from how large each image is drawn on the page, so a small photo is not cut down the way a full-page scan is.
Can I compress a PDF that is password-protected or digitally signed?
A password-protected PDF has to be opened first: remove the password with Unlock PDF, which needs it. A PDF with a certificate-based digital signature can be compressed, but any change to the file makes that signature show as invalid, so compress before signing.
Is it safe to compress a PDF online?
With PlumPDF, the PDF never leaves your device. It is opened and rewritten in your browser tab on your device, and images are re-encoded by your browser's own canvas. Nothing is uploaded or stored.