How to watermark a PDF
- Drop your PDF above. Drag it in, or click to pick a file.
- Type your watermark text. Opacity, size and angle live under Options. The defaults suit most documents.
- Click Add watermark, then Download. Every page is stamped on your device.
A watermark drawn in, not laid over
There are two ways to put a watermark on a PDF, and they differ in how easily it comes off.
The weak way adds it as an annotation or a separate optional layer: an object sitting above the page rather than part of it. It looks identical on screen, and it can be removed by anyone who opens the document in an editor and deletes the object, or in some cases by switching a layer off. Some viewers won't print it. Some won't show it at all.
This tool draws the text into each page's own content stream, which is the same place the document's real text and graphics live. There is no separate object to select and delete: the watermark is now part of the page's drawing instructions, in among everything else. Every viewer and printer reproduces it, and removing it means editing the page itself.
"Harder to remove" is not "impossible to remove", and it would be dishonest to imply otherwise. Anyone determined can edit the content stream, or simply render the page to an image and work from that. A watermark declares status and discourages casual reuse; it is not a security control. If the document must not be read by the wrong people, that's a password, and if part of it must not be read at all, that's redaction.
Making one that reads well
A watermark has one job, to be noticed without making the document unreadable, and the failure modes go in both directions.
- Opacity is the main control. Somewhere around 10–20% suits most documents. Below that it vanishes when printed, especially on an office laser printer, which is exactly when a DRAFT mark matters most. Above about 30% it starts competing with the text underneath.
- Diagonal beats horizontal for a full-page mark. It crosses the text at an angle rather than running along it, so it stays legible as a mark while leaving the sentences readable, and it is noticeably harder to crop out.
- Short text, large. One or two words at a size that spans the page. A long phrase shrunk to fit reads badly both as a mark and as a sentence.
- Check a dense page and a sparse one. A mark tuned on the title page often disappears over a full page of body text, or drowns a table.
For documents that circulate, put something useful in the text rather than just CONFIDENTIAL: the recipient's name, or a date. It makes a leaked copy traceable and reminds the reader which version they have. And watermark last: run it after merging or rearranging, so every page ends up stamped, and consider flattening a form afterwards so nothing sits above the mark.
Common uses for watermarking PDFs
- Mark a draft: DRAFT across every page of something still under review.
- Label confidential files: add CONFIDENTIAL before sensitive material goes anywhere.
- Brand a proposal: your company name across a proposal or a sample.
Frequently asked questions
How do I add a watermark to a PDF for free?
Drop your PDF above, type the text you want (CONFIDENTIAL, DRAFT, a client name), and click Add watermark. Every page gets stamped and the result downloads instantly. No cost, and no watermark on your watermark.
Can I control how the watermark looks?
Text, opacity, size, and diagonal or horizontal placement, all under Options. The defaults are large, light and diagonal, which suits most documents.
Does the watermark appear on every page?
Every page, stamped identically.
Is my document uploaded?
No. A file you are stamping CONFIDENTIAL is not a file to send to a random server first, so the stamping is done here in the page.