Compress a PDF
Get a heavy scan or slide deck under the attachment limit, and compare the size and readability trade-off. Your document never leaves your device.
Drop a PDF here or click to choose
Compressed on your device — never uploaded
How to compress a PDF
- Drop your PDF into the box above, or click it to pick a file.
- Choose a method. Rasterise pages repaints every page as an image and saves the most; Keep text re-saves the document with the words still selectable.
- For rasterising, pick the detail level — Screen for something that only has to be read on a phone, eBook for everyday sharing, Print if it might come out on paper.
-
Press Compress PDF and watch the page counter. The
before and after sizes appear together, so you can see the saving
before you download
report-compressed.pdf.
Why PDFs get so big
A PDF full of text is tiny. The megabytes almost always come from somewhere else, and knowing which one you have decides which method will help.
Scanner output is the usual culprit. A scanner or a phone scanning app does not read the words on the page; it takes a photograph of the sheet, often at 300 or 600 dpi, and wraps it in a PDF. Ten pages of that is a folder of large photographs pretending to be a document, which is why an eight-page contract can arrive at 40 MB.
Embedded images come next. Slide decks, brochures and reports carry the pictures at whatever resolution they were pasted in at — usually straight off a camera, far beyond anything a printed page can show.
Fonts and edit history make up the rest. Every typeface used has to be embedded, and a file that has been through several editors accumulates objects nobody references any more, along with incremental saves stacked on top of one another.
The two methods, and what each really does
Rasterise pages draws each page at the resolution you picked, encodes it as a JPEG and rebuilds the document at the original page sizes. Whatever was making the file heavy — a 600 dpi scan, a camera photograph, a dozen embedded fonts — collapses into one picture per page at a sensible resolution. This is where the big numbers come from, and the cost is real: the text becomes pixels, so it can no longer be selected, searched, copied or read aloud.
Keep text leaves the page contents completely alone. It parses the document, strips the metadata, drops what is no longer referenced and writes everything back into compressed object streams. Text, links, bookmarks and form fields all survive. On a file that has been edited and re-saved a few times this genuinely helps; on a clean export it may do almost nothing, and the tool will say so rather than pretending otherwise.
| What you have | Method | Why |
|---|---|---|
| A scan of a signed document | Rasterise | It is already pictures, so nothing searchable is lost |
| A slide deck with photographs | Rasterise | The images are the weight; screen resolution is plenty |
| A contract you need to search | Keep text | Rasterising would make Ctrl+F useless |
| A form with fields to fill in | Keep text | Rasterising flattens the fields into a picture |
| A long report where only some pages matter | Neither | Extract the pages you need — fewer pages beats better compression |
Why compress in the browser?
The PDFs people most want to shrink are the ones they should be least willing to hand over: a passport scan for a visa application, a payslip for a landlord, a medical letter, a signed contract. The usual online compressor asks you to upload all of it to a server you know nothing about, in exchange for a few megabytes.
This tool does the work where the file already is. Your browser opens the document, renders or rewrites it locally and hands you back a new file that was created on your own machine. There is no upload step, no account, no watermark and no retention policy to read, because there is nothing on our side to retain. You can check that boundary yourself: open the browser's network tab and confirm that no request carries your PDF or anything close to its file size out for processing.
Frequently asked questions
Is my PDF uploaded to a server?
No. The document is read by pdf.js, the open-source renderer built for Firefox, and written back out by pdf-lib — both compiled to run inside your own browser tab. The page, processing engines and advertising can make ordinary network requests, but your PDF is not attached to any of them; there is no processing queue and no server copy is kept.
Which of the two methods should I pick?
If the PDF is a scan, a photographed document or a slide deck full of pictures, choose Rasterise pages — that is where the weight is and where the savings are. If you need the text to stay selectable and searchable, choose Keep text and accept a smaller gain. When you are unsure, run Keep text first: it is quick, and if the result is barely smaller you will know the bulk is images rather than structure.
How much smaller will my PDF actually get?
It depends entirely on what is inside. A scanned document at 300 dpi typically loses 70 to 90 per cent of its size when rasterised at the eBook preset. A slide deck with photographs usually halves. A text-only report compressed with Keep text often moves only a few per cent, because there was never much fat to trim. The tool shows the before and after size for every run, so you never have to guess.
Will the text still be selectable and searchable?
With Keep text, yes — every glyph, link, bookmark and form field survives, because the page content is not touched at all. With Rasterise pages, no. Each page becomes a picture of itself, so the words become pixels: you cannot select them, search them, or have a screen reader read them out. That is the price of the larger saving, and it is why the tool says so before you press the button.
What happens to comments, highlights and stamps?
Keep text leaves every annotation exactly where it was. Rasterise pages draws each page the way a printer would, so an annotation only survives if it is marked as printable — which most are, including comments and highlights added by Acrobat, Preview or a browser. Some tools write annotations without that flag, though, and those are on screen in your reader and simply absent from the compressed file. If a document carries marks that matter, open the result and check them before you delete the original.
Can it open a password-protected PDF?
It depends which lock. A PDF that opens in any reader but is marked “no editing” carries an owner password only; that lock is taken off on your device as the file is read, the tool tells you it happened, and both methods work on it. A PDF with an open password is a different thing: it has to be unlocked before anything can read it, and this will tell you so rather than producing a broken file. There is nowhere on this site to type a password in. Open it in your usual reader with the password, save an unprotected copy, then bring that copy here.
Is there a size limit?
There is no limit imposed by us, because there is no upload to limit. The real ceiling is your device: every page is rendered in memory, so a several-hundred-page scan on an older phone can run out of room. Pages are processed one at a time with the count shown as it goes, and you can cancel at any point. If a huge document struggles, split it first and compress the halves.