Add a watermark to a PDF

No. The tool runs entirely in your web browser using JavaScript. Your files are read from your device, processed in memory and saved straight back to it. They are never uploaded, stored or seen by anyone.

Yes. The preview shows the first page you’re watermarking with the text drawn where it will be, at the size, colour, opacity and angle you chose, and it updates as you change them. After downloading, “Change settings” takes you back to the same PDF to adjust them.

It’s drawn into the pages, on top of the text and images, so it can’t be switched off in a PDF reader. Someone with PDF editing software could still delete it, so treat a watermark as a clear label rather than as security.

Letters, numbers and punctuation used in English and other Western European languages, accents, curly quotes, dashes and the euro sign included. The watermark uses the PDF’s built-in Helvetica font, which can’t draw characters such as Chinese, Arabic or emoji; the tool names any it can’t draw before you start.

It’s semi-transparent by default (30% opacity), so the page underneath stays readable. Lower the opacity for a fainter mark, or raise it to make the watermark stand out.

As many as fit on the page with a small gap between them, up to 1,000 per page. On a very large page with small text, such as a poster, the copies are spaced further apart, so the file stays small and quick to open.

No. The watermark is marked as decoration (an “artifact” in PDF terms), which tells screen readers and read-aloud tools to skip it rather than read it out in the middle of your text. It’s drawn in the PDF’s built-in Helvetica Bold font, which isn’t embedded in the file, so a PDF/A archive file won’t stay PDF/A-conformant once watermarked.

Yes. There is no sign-up and no daily limit, and the only mark added to your PDF is the watermark you choose. Because all the work happens on your own device, there are no servers to pay for.