Compress PDF

Make a PDF smaller in your browser, and be told what it costs before you do. Nothing is uploaded.

Free, no limit Nothing uploaded No watermark Works on mobile

Drop your PDF here

It compresses the moment you drop it. Nothing is uploaded.

Choose a file

What is actually big, and what it costs to fix

A PDF that will not fit under an upload limit is almost never big because of its text. Text is a few kilobytes a page. It is big because of images, and usually one particular kind: a scan, which is a photograph of a sheet of paper stored at whatever resolution the scanner or the phone was set to. Ten pages at 600 DPI is thirty megabytes of photographs of white paper.

Reducing those to a sensible resolution and a sensible quality is where nearly all of the saving comes from, and on a scan it costs nothing that matters, because a scan was already a picture. There was no text underneath to lose.

On a document that came out of a word processor it costs a great deal, and this is the part most compressors do not tell you: the text stops being text. It becomes part of the picture, so it cannot be selected, searched or read aloud, and it goes soft when you zoom. So this page looks at your file first and says which kind it is before you press anything.

A large PDF being reduced to a much smaller one
How it works

Three steps, no upload

Your browser reads the images and writes the document. There is no queue and no waiting.

1

Add your PDF

Drop the document onto the tool or pick it from your device.

2

Say which pages

A file per page, or one file with the pages you name. Order is respected.

3

Download

One document, with the text still text. Nothing was uploaded to get it.

How the file gets smaller

Every page is opened and drawn by pdf.js, Mozilla's PDF engine, at the resolution that gets the file as small as it can go while the page still reads. That drawing is then encoded as a JPEG and placed into a new document by the PDF writer this site uses everywhere else, which puts a JPEG in without touching it.

Two things happen at once and both matter. The resolution comes down, which is where most of the saving is: a page scanned at 600 DPI holds four times the pixels of the same page at 300 and looks no better on a screen. And the JPEG quality comes down, which throws away detail your eye was unlikely to find.

The page keeps its original size in points, so an A4 document is still A4 and prints at the size it was made for. What changes is how many pixels are inside it.

There is nothing to set and nothing to press. Every document gets the strongest treatment that keeps a page readable the moment it is dropped, and if the file somehow does not come down, the tool quietly tries harder before it reports back. Asking somebody to pick between three levels asks them to predict a result they cannot see yet, and asking them to press start asks a question with one answer.

Before any of that, the first few pages are checked for text. A scan yields almost none; a document written in a word processor yields thousands of characters. That number is used for one thing only: if your document had real text in it, the page says so underneath the result, because that is the one cost worth knowing about. A scan is told nothing, since a scan had no text to lose.

What it does, and how far it will go

AttemptLongest sideAn A4 pageWhen it is used
Firstup to 1400 pxabout 120 DPIEvery document. This is usually the end of it, and a scan typically loses eighty to ninety percent.
Secondup to 1050 pxabout 90 DPIOnly if the first attempt barely moved the size.
Thirdup to 820 pxabout 70 DPIA last try, for a file that refuses to come down.

You do not choose between these and you are not asked to. The tool starts at the first, and only goes further if the result was not meaningfully smaller than what you gave it, because going harder for its own sake costs sharpness and buys very little.

A page that is already smaller than the cap is not enlarged. There is nothing to gain from inventing pixels, and a great deal of file size to lose.

Those savings are for scans, which is what people compress. A PDF of typed text is small already and will usually grow, because turning a page of letters into a photograph of a page of letters takes more space than the letters did. When that happens you are told, and no download is offered: handing back a bigger file with a button on it would invite you to send it.

Why none of this leaves your device

Think about what people actually turn into PDFs. Passports and visas. Bank statements for a loan application. Degree certificates. Rental agreements with a signature on them. Medical letters. Almost every one of those is a document you would not hand to a stranger.

An online converter that works the ordinary way asks you to do exactly that. Your file goes to a server you know nothing about, in a country you were not told, and is processed and stored for some period described in a policy nobody reads. Most of those services are honest. You have no way of checking which ones.

This page removes the question. The conversion runs in your browser, using the image decoder your browser already has and a PDF writer that is part of the page. No file is transmitted, so there is nothing on our side to store, scan, sell or lose. You can disconnect from the internet after the page loads and it will still work, which is the simplest proof there is.

One thing to be straight about: rendering the pages uses pdf.js, an open source engine written by Mozilla and the same one Firefox uses, and the new document is written by code belonging to this site. Neither sends your file anywhere. We serve our own copy of pdf.js from this domain rather than loading it from a content network, so opening this page tells nobody else that you did.

Drop it and it is done

Most compressors open with a question: light, balanced or strong. It is a question nobody can answer, because the honest answer is "whichever one gets me under the limit", and you cannot know which that is until you have tried. Then they ask you to press start, which is a question with one answer.

So this page does neither. Drop the document and it compresses immediately, going for the smallest file that still reads: each page capped at 1400 pixels on its longest side, which is about 120 DPI on A4, and encoded at a quality that holds up on a screen and prints acceptably. On a scan that is normally eighty to ninety percent off. A download button appears beside the result when it is finished.

If your file is stubborn and that first pass did not really move it, the tool tries again harder on its own, twice, before it reports anything. You see one number at the end: how much smaller it got.

When not to use this

If your PDF is a contract, a report or anything typed rather than scanned, and the text matters, this is the wrong tool and the page will tell you so when you drop the file. What you want instead is to remove the pages you do not need with our split page, or to export a smaller PDF from whatever produced it.

It is also worth knowing that a well made PDF cannot be compressed much by anybody. If your file is already small for what it contains, every compressor will either make it barely smaller or make it larger. This one will tell you which happened rather than quietly handing back a bigger file.

How this compares with the alternatives

An online compressor that uploads

Most of them do the same thing this page does, on a server, and few say so. The document goes to a machine you know nothing about, and the thing people compress is a passport scan or a bank statement for an application.

Scanning at a lower setting in the first place

Much the better answer when it is available. 300 DPI is plenty for a document and 600 is almost always a waste. If you are about to scan twenty pages, change the setting rather than compressing afterwards.

Acrobat's Reduce File Size

Better than this, and it should be: it can downsample the images inside the file while leaving the text as text, which is the thing a browser cannot do without shipping a full PDF parser. If you have Acrobat, use it.

Removing pages instead

The most underrated option. If the size limit is the problem and half the document is pages nobody asked for, our split page takes out only what you need and loses nothing at all.

If something does not look right

The file got bigger

Then it was already efficient, and there was nothing here to win. A PDF made of text and vector drawings is tiny to begin with; turning it into pictures costs more than it saves. Keep the original.

I cannot select the text any more

That is what compressing this way does, and the page warned you before you pressed the button. The original still has its text. If you need both smaller and selectable, remove pages instead, or export a smaller PDF from whatever produced it.

Small print has gone soft

Compressing a scan means storing fewer pixels, and below roughly 120 DPI small print starts to blur. There is no setting to move here, so if the result is not readable enough, keep your original and get under the limit another way: take out the pages you do not need with our remove pages tool, which loses nothing at all.

It says the PDF is password protected

It is. Open it in a reader with the password and save an unprotected copy first; nothing can read a locked document without it.

A long document is slow

Every page is rendered and re-encoded one at a time, on purpose. Doing them at once would run a phone out of memory. A hundred page scan takes a while and is working throughout.

The pages came out blank

Some unusual PDFs defeat the renderer. If a page is blank here it will often be blank in Firefox too, since it is the same engine. Opening the file in another reader and saving a fresh copy usually fixes it.

Free, with no account and no watermark

No sign-up, no daily limit, no watermark and no page cap. There is no paid tier holding back the compression, and no weaker free setting: every document gets everything the tool can do, because the work happens on your computer and costs us nothing.

The result keeps your own name with a word added, so statement.pdf becomes statement-compressed.pdf, and the download button sits beside it. Your original is untouched on your device, which matters here more than usual: nothing is saved until you press download, so if the result is not good enough you have lost nothing.

Both numbers are shown, before and after, because a compressor that does not tell you what it achieved is asking you to take its word for it. If the saving is not worth what it cost, keep the original.

FAQ

Compress PDF

The questions people ask most about this conversion.

Drop it on the tool above. That is the whole thing: it starts immediately, compresses as hard as it can while keeping the pages readable, and puts a download button next to the result with the size before and after.

If your PDF has real text, yes: it becomes part of the picture and can no longer be selected or searched. The tool says so underneath the result when it happens, and your original on your device is untouched, so nothing is lost by finding out.

Because a scan is already a photograph, so there is no text to lose. All that changes is the resolution and the compression of a picture, and most scans are stored at far higher resolution than anyone needs.

No. It is opened, rendered and rebuilt entirely inside your browser. Nothing is transmitted, which matters here because the documents people compress are usually private.

It does not hand you a bigger file. If nothing it tries comes out smaller, it says the original was already efficient and offers no download, because a PDF full of text and vector drawings is tiny to begin with and turning it into pictures costs more than it saves.

Because both ask a question with one answer. There is only one thing anybody wants done to a PDF on this page, so it happens the moment you drop the file, as far down as it can go while a page still reads.

Not exactly. It compresses as far as it sensibly can and shows you the result, but hitting a precise target would mean many passes over a large document. If you need an exact size for images rather than a PDF, our image compressor does that.

No. A locked document cannot be opened without its password. Unlock it in a reader first and save an unprotected copy.

Completely, with no limit on how many images you convert or how large they are. There is no account, no paid tier and no watermark, because the conversion runs on your device and costs us nothing to provide.

No. There is no app, no extension and no plugin. The page you are on is the whole program, and it works the same on Windows, macOS, Android and iPhone.

No. There is no watermark, no logo and no added page, however many images you convert.

Yes, on both iPhone and Android. Pick images straight from your gallery and the PDF is saved to your downloads like any other file.

No. This page makes a PDF out of images. Reading an existing one needs a full PDF renderer, which is a large program we would have to load from somewhere else, and that would break the promise that nothing leaves your device.

Yes. A pdf size reducer, a pdf reducer and a pdf compressor online all describe this page. The names differ because people describe the same job differently; the job itself does not change.
More tools

Other ways to get there

Same engine, different job. Every one runs in your browser.

All PDF tools

JPG to PDF

Turn JPG files into a single PDF, in your browser.

Image to PDF

Turn image files into a single PDF, in your browser.

PNG to PDF

Turn PNG files into a single PDF, in your browser.

PDF to JPG

Turn PDF files into a single PDF, in your browser.

Need a different conversion?

Over a hundred free tools, all running in your browser. Nothing is uploaded and nothing is capped.

Browse all tools Contact us