💧 Add Watermark to PDF
Add a text watermark across your PDF pages — set the wording, size, opacity and angle, then download. The file is processed on your device.
How the add watermark to pdf works
The tool loads the PDF with pdf-lib, embeds a standard Helvetica Bold font, and draws your text onto each selected page at the opacity and size you choose. With the diagonal option the text is rotated 45° and centred by stepping back along its own baseline, so it sits squarely in the middle of the page whatever its length. Pages are edited in place — the rest of the document is untouched — and the whole operation happens in your browser.
A watermark drawn this way becomes part of the page content, so it will not simply toggle off in a viewer. It is not a security measure, though: anyone determined can edit the PDF or cover the text. Use it to mark status — DRAFT, SAMPLE, INTERNAL — rather than to protect a document. If you need genuine restriction, add a password with the PDF protect tool instead. Keep opacity low (10–20%) so the underlying text stays readable.
Frequently asked questions
How do I add a watermark to a PDF?
Choose your PDF, type the watermark text, set size and opacity, and download. By default the text is drawn diagonally across the centre of every page. Everything happens in your browser — the file is never uploaded.
Can I watermark only certain pages?
Yes. Leave the page field empty to watermark every page, or enter a range like 1-5 or 2, 4, 7 to mark only those pages.
Is the watermark removable?
It is drawn into the page content rather than added as a separate toggleable layer, so it will not switch off in a normal viewer. It is not tamper-proof, though — a determined person with PDF editing tools can remove or obscure it.
Does a watermark protect my document?
No. It marks status and discourages casual misuse, but it does not restrict opening, copying or printing. For actual restriction, use password protection instead.
What opacity should I use?
Around 10–20% usually reads clearly as a watermark while leaving the document text legible underneath. Higher values start to compete with the content.
Is my PDF uploaded?
No. It is parsed and rewritten by pdf-lib inside your browser, so the document never leaves your device and the tool works offline once loaded.