Compress PDF
Reduce PDF file size while keeping it readable.
How to use Compress PDF
- Add your PDF Drag the file onto the box, or tap it to pick a file from your device.
- Choose a level Start with Recommended. Move to Maximum only if the file still needs to be smaller.
- Compress Press Compress PDF. It runs right here in your browser — nothing is uploaded.
- Check and download You will see the real before and after size. Download the file, or try a stronger level.
Working on it…
You can keep this tab open — we will tell you the moment it is done.
Wish granted.
Your file never leaves your device. This tool does the work inside your browser, so nothing is uploaded to us or to anyone else — and it works even with your Wi-Fi switched off.
A PDF that will not fit in an email is almost always a PDF full of images saved at a far higher resolution than anyone will ever look at. Compress PDF re-encodes those images at a sensible size, strips duplicated data, and rebuilds the file structure — so the document still reads correctly but takes up a fraction of the space.
What actually changes inside the file
Three things account for nearly all the saving. Embedded images are downsampled to a resolution that still looks sharp on screen and in normal printing. Fonts are subset, so only the characters the document uses are carried. And the file structure itself is rewritten with compressed object streams, which removes the slack that accumulates every time a PDF is edited and re-saved. Text stays as text throughout — it remains selectable and searchable, and the page count never changes.
Choosing a level
Recommended targets around 150 DPI, which is indistinguishable from the original on a screen and fine for everyday printing. High compression drops to roughly 110 DPI and is the right choice for a document that only needs to be read, not printed. Maximum goes to 72 DPI — screen resolution — and produces the smallest file by a wide margin, but photographs will visibly soften. If you are sending a scanned contract, Maximum is usually still perfectly legible.
When a PDF cannot be compressed
A PDF that is mostly text, or one that has already been optimised, has very little left to remove. When that happens we tell you so and hand back your original file rather than a pointless re-save that gains nothing. We would rather say "this is already as small as it goes" than show you a 0.4% saving and call it a result.
Frequently asked questions
Will compressing damage my PDF?
No. The page count, text and structure are preserved, and we verify the output opens correctly before handing it to you. Images are re-encoded at a lower resolution, which is where the saving comes from — at the Recommended level this is not visible on screen.
How much smaller will my file get?
It depends entirely on what is inside. Image-heavy documents and scans routinely drop by 70–90%. A text-only PDF may not shrink at all, because there is nothing to remove. We show you the real figure rather than an estimate.
Is there a file size limit?
Files up to 100 MB. That covers the overwhelming majority of documents; if yours is larger, splitting it first usually works well.
What happens to my file afterwards?
Nothing happens to it, because nothing was sent anywhere. Compress PDF runs inside your browser: your file is read from your own disk, worked on in this tab, and handed back. We never receive it, so there is nothing for us to keep, read or delete.
Can I compress a password-protected PDF?
Yes, if you know the password — enter it in the optional field. We cannot open a PDF you cannot open yourself.