Compress PDF
Reduces the weight by recompressing the images inside the document. Text stays text: you can select it, search it and a screen reader still reads it, exactly as before.
Your file stays on your device: nothing is uploaded
How it works
On embedded images the tool reduces them to the resolution you choose and recompresses them: that is what lightens scans and photo-heavy documents. On text-only documents the weight is in the embedded typefaces instead, and there the tool does two things that take nothing away from what you see: it reduces every typeface to just the letters the document actually uses — often ninety out of three thousand — and merges blocks of data repeated identically, which in some documents are half the file. Text stays selectable and searchable either way. If the result would be larger than the original you get the original back, and we say so. If the document is made of scans you can also turn it black and white: text pages weigh a fraction of what they did, pages with photos stay as they are.
Frequently asked questions
- Why did my PDF shrink so little, or not at all?
- Usually for one of two reasons: whoever made it had already optimised it, or its images are in formats the tool leaves as they are, such as some black-and-white scans. The summary at the end tells you which. As a last resort there is rasterising, in the advanced options, which makes the text no longer searchable.
- Will the images look worse after compressing?
- With “Recommended”, each image is brought to 150 DPI at the size it appears on the page: meant for reading, archiving and sending by email. If you need to reprint, pick “High quality” (200 DPI) in the advanced options. Images that are already smaller are never enlarged.
- Can I compress a digitally signed PDF?
- Yes, but in the compressed file the digital signature will no longer show as valid: that happens with any change to the document, however small, and the tool tells you so. If the signature matters, send the original to whoever needs to check it.
- My PDF is over 50 MB: what can I do?
- The limit is 50 MB per file. For a bigger document, split it into blocks of pages with “Split PDF”, compress the parts and put them back together with “Merge PDFs”. Bear in mind that bookmarks and form fields don’t survive the split.
- Can I make a scanned document much lighter?
- Yes: if the PDF is made of scanned pages, the “Black-and-white document” choice appears. Text pages become pure black and white and weigh a fraction of what they did, with sharp black text; colours and light greys disappear, though, and pages with photos stay as they are. Text the document already contained, such as text from character recognition, stays searchable.
Your files are never uploaded. Anywhere.
Your file stays in your browser’s memory: it is read, processed and written back here. There is no server to send it to.
- Processed locallyEverything happens on your device.
- Nothing to upload, nothing to wait forNothing to upload, no waiting.
- No files to deleteWe keep nothing: nothing reaches us.