Compress PDF
Make your PDF smaller without wrecking it — we shrink the images and leave your text perfectly crisp. Free, instant, and private. Your file never leaves your browser.
Drop a PDF here, or click to choose
Shrinks images, keeps text crisp and selectable
Choose PDFDrop several at once to batch them — on your device Pro
The scans other tools give up on
We tested a 27 MB scanned book that big-name tools returned almost unchanged. DiemDesk rebuilt it page by page — without the file ever leaving your browser.
27.1 MB6.8 MB
75% saved on Maximum
Other tools managed about 1%
0 bytes of your file have left this device. Counted live in this tab, not claimed — open your browser’s Network tab and watch.
What this does to your file
The whole list, so there are no surprises after you download.
- Images
- re-encoded, smaller
- Text and vector art
- untouched
- Fonts
- kept, subset
- Metadata and author
- preserved
- Digital signatures
- invalidated
- Runs on
- your device
Where this won’t help
Cases we’re the wrong tool for, and what to use instead.
A PDF that is mostly text. There is little to squeeze out. Expect a few percent, not seventy.
Very large files on a phone. The browser tab can run out of memory. A desktop will get through it.
Hitting an exact size. This tool aims for a quality level, not a number. Compress to a size →
Print-shop preflight. We do not do PDF/X colour conversion. Acrobat Pro is the right tool.
How it works
- 1
Drop your PDF in, or click to choose it.
- 2
Pick a level — Recommended is the best balance of size and quality.
- 3
Click Compress and your smaller PDF downloads instantly.
Frequently asked questions
Is it really free?
Yes — compressing PDFs is completely free, with no signup, no watermark, and no daily limits.
Is my PDF uploaded to a server?
No. Compression runs entirely inside your browser using your device, so your file never leaves your computer.
Will my text get blurry?
No. We only shrink and re-encode the images inside the PDF — the text and vector graphics are left completely untouched, so they stay crisp and selectable.
How much smaller will it get?
It depends on the file. Image-heavy PDFs (scans, photos) often shrink by half or more. PDFs that are mostly text are already small, so there may be little to gain — and we never hand back a larger file.
Another tool said my PDF can’t be compressed. Can DiemDesk still shrink it?
Often, yes — especially scanned documents. Many tools give up on scans stored in formats like JPEG 2000 and hand the file back nearly unchanged. DiemDesk detects those pages and rebuilds them at the right resolution: in our test, a 27 MB scanned book that other tools returned about 1% smaller came out 60–75% smaller — still crisp and readable, and the file never left the browser.
Which level should I choose?
Recommended suits most files. Choose Light to keep the most image detail, or Strong for the smallest possible size when quality is less critical.
Is anything besides images touched?
Two lossless extras: embedded fonts are slimmed (unused glyph outlines removed — the text itself is untouched), and hidden metadata (author name, editing history, the XMP packet, embedded thumbnails) is cleaned out. That saves bytes and doubles as a small privacy win — the document looks and renders exactly the same.
Is there a file size limit?
No server limit — nothing is uploaded, so it all runs in your browser. The practical limit is your device’s memory rather than a fixed number: most PDFs are fine, and very large scanned files simply take longer (a desktop with more RAM helps).
What usually comes next
The step most people take after this one — and why.
Last improved
Changes to this tool specifically, not the site.
- New feature
Tool pages now suggest what usually comes next
Tool pages now tell you the step that usually comes after the one you just did, and why it follows. Compress a PDF and it points at the Share-Safe check, because you compressed it in order to send it and you should know what is hidden inside it first. Sign one and it offers to flatten it, so the signature cannot be dragged off the page afterwards. Scan a document and it offers OCR, because a photo of text is not text. It only appears where a step genuinely follows — on a tool where nothing does, there is nothing there, which is deliberate. This is the idea we picked over showing your recently used tools: recency only tells you what you already know you opened, and shows a first-time visitor nothing at all, while the next step is the same for everyone and works the first time you land here from a search.
- New feature
See exactly what compression changed, instead of squinting
The quality preview used to put the original and the compressed page side by side and leave you to spot the difference. At the gentler settings there is nothing to spot — which is the whole point, but it reads as though the tool is broken. So it now tells you instead of asking you. It says in words whether anything visible changed, and it lists what was actually done: text untouched and still selectable, and the page image resized from one size to another at a stated quality. There is a "Show what changed" view that paints the page black where nothing moved and bright where it did, amplified ten times, because the changes worth seeing are small ones. And when a page is already close to the smallest size that stays readable, it now says so plainly — that every setting will produce the same page and only the file size differs — instead of leaving you switching between four buttons wondering why nothing happens. None of it is an estimate: it is measured from the actual page your settings will produce, on your device, before you commit to anything.