macOS ships with Preview, which is genuinely good at some PDF work — it can rotate pages, and you can drag pages between two open documents. But Preview is fiddly for anything beyond that, it can't edit existing text, and its page-thumbnail dragging is easy to get wrong. A browser tool gives you a clearer interface for the same job, with no upload and no Acrobat subscription.
Hitting an attachment or upload limit is the most common reason people go looking for a PDF tool at all — the portal rejects a 12 MB file and you need it under 5 MB right now.
2Choose a level: Light keeps text selectable, Balanced suits most documents, Strong makes scans as small as possible.
3Click “Compress PDF” and download the smaller file — you'll see the before and after sizes.
Click to browse and the standard macOS file dialog opens — or just drag the PDF from Finder or your desktop straight onto the page, which is usually faster.
Where the finished file is saved on Mac
Your browser saves the result to ~/Downloads by default, and it appears in the downloads list in the toolbar. From there drag it straight into Mail, Finder or a Slack message.
What Mac can’t do on its own
Preview can rotate and reorder pages, but it cannot edit existing text, fill non-interactive forms, run OCR on a scan, or convert a document to other formats. Adobe charges a monthly fee for those; this doesn't.
FAQ
Why not just use Preview on my Mac?+
Preview is fine for rotating pages or dragging thumbnails between two open PDFs. It can't edit existing text, OCR a scan, or convert formats — and its drag-based page shuffling is easy to get wrong on a long document.
Does this work on Apple Silicon Macs?+
Yes. It's a web page, so it runs identically on M-series and Intel Macs, in Safari, Chrome, Arc, Firefox or Edge.
How much smaller will my PDF get?+
It depends entirely on what's inside. Scanned documents and photo-heavy files often shrink by 70–90%. A PDF that's mostly text may only shrink a little, because there wasn't much to remove in the first place — we'll show you the real before and after numbers rather than a vague promise.
Will compressing ruin the quality?+
Light is lossless — nothing is degraded at all. Balanced re-encodes pages as images at a quality that still looks clean on screen and in normal printing. Strong prioritises the smallest possible file, so fine detail softens; it's meant for scans you need to read rather than reproduce.
Why is my text no longer selectable after compressing?+
Balanced and Strong work by turning each page into an image, which is what makes big files shrink dramatically — but images have no text layer. If you need to search or copy text afterwards, use the Light level, which keeps the document's text intact.
My file didn't get smaller — why?+
Some PDFs are already fully optimised, and squeezing them further would actually make them bigger. When that happens we hand back your original file untouched instead of a larger “compressed” version. Trying a stronger level usually helps.
Is there a file size limit?+
No fixed limit. Compression runs on your own device, so the practical ceiling is your browser's memory — everyday documents up to around 100 MB work comfortably.
Is pdfcdf free to use?+
Yes. Every tool on pdfcdf is completely free, with no account, no watermarks, and no limits on how many files you process.
Are my files safe? Do they get uploaded?+
Your files never leave your device. Every tool runs entirely in your browser, so your documents are processed locally and are never uploaded to a server or seen by anyone.
Do I need to create an account or sign up?+
No. pdfcdf works instantly with no sign-up, no email, and no software to install — just open the tool and go.
Does it work on mobile phones and tablets?+
Yes. pdfcdf runs in any modern browser on phones, tablets, Mac, Windows and Linux — nothing to download.
