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Compress a PDF

Shrink a document that is too heavy to email or upload. You choose the resolution and quality, and see the before and after before downloading — all inside your browser.

Drag and drop your PDF here

or click to select from your device

PDF only • up to 10 files • up to 100 pages per file

🔒

Processed on your device: Your documents are processed in your own browser and never pass through any server.

Verify it yourself
  1. Press F12 and open the Network tab.
  2. Add a file above and run the tool.
  3. You will see the page’s own scripts, its ads and its traffic measurement — and no request carrying your file.
  4. Stronger still — and the order matters: run it once while online, then disconnect, then run it again. It still works, because by then the page already holds everything it needs.

⚠ Read this before you compress

This rebuilds every page as an image. The file gets smaller, but the text stops being text: no selecting, no copying, no searching, and a screen reader can no longer read it. For a scanned document that is already images, you lose nothing. For a text document, you lose a lot — and it will probably come out bigger, because vector text is far lighter than a photograph of a page.

72%

Around 70% is the sweet spot for scans. Below 50% the artefacts start showing on text.

📉 Real numbers

Shows the before and after, not a vague promise.

⚠ Says when it fails

If the file grows, it tells you to keep the original.

🔒 Nothing is uploaded

The document is rendered and rebuilt locally.

What compressing a PDF actually means

A PDF can hold two very different things. It can hold instructions — draw this letter, in this font, at this position — which is how a document exported from a word processor works, and it is extraordinarily compact. Or it can hold photographs of pages, which is what a scanner produces, and that is where the weight comes from. Knowing which one you have decides whether compression will help or hurt.

Why this makes some files bigger

Compression in a browser means rasterising: rendering each page and storing the result as a JPEG. For a scan that is a straight win, because you are replacing a big image with a smaller image. For a text document it is a disaster in both directions — a page of text might occupy a couple of kilobytes as instructions and two hundred as a photograph. The tool measures the result and tells you when that happened, instead of handing you an inflated file labelled "compressed".

What you give up

Everything that depends on the text existing as text. You cannot select or copy a sentence, search inside the document, or have a screen reader announce it. An automated system that reads invoices will no longer find the fields. If any of that matters for the file you are about to send, compression is the wrong operation and a lighter scan or a different export is the right one.

Choosing the settings

Resolution decides the size far more than quality does, because it changes the pixel count on both axes at once. 110 DPI is comfortable on screen and is the sensible default; 72 DPI is for documents that will only ever be looked at on a phone; 150 and above is for something that may be printed. Quality around 70% is where JPEG stops wasting bytes without visible damage on a scan.

Why it runs in your browser

Documents that are too heavy to send are rarely trivial ones — they are contracts, medical records, scanned identity papers, a dossier someone put together. Uploading those to a compression service is handing over a full copy. Here the rendering is done by PDF.js and the rebuilding by pdf-lib, both running on this page.

How to tell what kind of PDF you have

Open it and try to select a line of text with the mouse. If the selection highlights words, the document is vector text and compressing it here will almost certainly make it bigger — the useful move is to re-export it from whatever produced it, at a lower image quality. If the cursor just draws a rectangle over the page, it is a scan: every page is already a photograph, there is nothing to lose, and the saving is usually dramatic. A 1 MB scan commonly drops below 200 KB at 110 DPI without becoming hard to read.

Want to go deeper? Read our guide: How to make a PDF smaller for email and upload forms

Frequently asked questions

Because it was a text PDF, not a scan. Text is stored as drawing instructions, which are far lighter than a photograph of the same page. Rasterising it inflates the file. When that happens the tool says so — keep the original.

No, and that is the trade. Every page becomes an image, so there is no text layer left to select, copy, search or read aloud. If you need those, do not compress this way.

110 DPI for anything that will be read on screen. 72 only for phone viewing. 150 or 200 if the document may be printed. Resolution changes the size much more than the quality slider does.

No. It is read into memory, rendered and rebuilt in your browser. Open the Network tab and compress one: no request carries the file.