Your file stays on your device
Stamping happens inside your browser. The PDF you choose is never sent to a server, which is why this keeps working once the page has loaded, even offline.
How to add a watermark to a PDF
- Drop your PDF into the box above, or click to choose it.
- Choose text or an image. For text, type it and pick an angle and layout; for an image, attach a JPEG and choose where it sits.
- Set the size or width and the opacity.
- Choose over or under the page, leave the pages field empty for every page, then select Add watermark and download.
Over and under
"Over" draws the watermark on top of the page — the usual choice. "Under" draws it beneath the page's own content, where it is hidden by anything opaque, such as a scanned page. Under is mainly useful on pages with transparent or partial backgrounds.
Text is set in a built-in font
Watermark text uses Helvetica, one of the fonts every PDF reader carries, so nothing is downloaded or embedded. Its built-in encoding covers Latin letters, digits and common punctuation; a character outside that is named so you can change it.
Frequently asked questions
Can this remove a watermark another tool added?
No — this tool only adds one. A watermark baked into a page's own content cannot be told apart from the rest of the page.
Does the image watermark reduce photo quality?
No. The JPEG is embedded exactly as given, the same way the JPG-to-PDF tool works — nothing is decoded or re-encoded.
Can I watermark a password-protected PDF?
Yes. You will be asked for the password when the document is read. The watermarked file is not password-protected.