# Add a Watermark to a PDF - Free, In Your Browser

Page: https://hirantha.me/tools/pdf-watermark
Part of: Hirantha Sandaruwan Lakshan free tools (https://hirantha.me/tools)
Updated: 2026-07-31

Stamp text like CONFIDENTIAL or DRAFT across every page.

This is a free tool that runs in the browser: open the page to use it. File tools process files on the visitor's own device; files are never uploaded or stored. No account, sign-up, payment or watermark.

Stamp diagonal text like CONFIDENTIAL, DRAFT, or a company name across every page of a PDF, with control over color, size, and opacity. Processing happens entirely in your browser - nothing is uploaded.

The watermark text is measured and centered on each page before being rotated 45 degrees around its own center, so it appears consistently placed regardless of page size.

Opacity, size, and color are adjustable with a live preview over the first page, so you can see roughly how the result will look before processing the whole document.

The same text is stamped onto every page in a single pass, keeping the original page content and quality untouched underneath it.

Q: Does this work on password-protected PDFs?
A: Yes - enter the password when prompted and the watermark is applied after the file is unlocked.

Q: Can I change the watermark's color and transparency?
A: Yes, choose between gray, red, or black, and adjust the opacity slider from subtle to bold.

Q: Will the watermark cover up the original text?
A: At the default opacity it sits behind the readability of the original content - increase opacity for a bolder, more visible stamp.

Q: Is my document uploaded anywhere?
A: No, the watermark is drawn onto each page entirely in your browser tab.

Q: Can I put the watermark behind the text instead of over it?
A: It's drawn over the page content, with opacity as the control. Lowering the opacity keeps the underlying text fully readable, which achieves the same effect visually.

Q: Can I use an image or logo as a watermark?
A: Not here - this stamps text. To place a logo, use the PDF signing tool, which embeds a transparent PNG anywhere on the page.

Q: Can I watermark only certain pages?
A: The watermark goes on every page. To mark a section only, split the PDF, watermark that part, and merge it back.

Q: Can someone remove the watermark?
A: Anyone with a PDF editor can edit any PDF. A watermark marks status and discourages casual reuse; it isn't a security control.

Sources: Portable Document Format (PDF) (https://en.wikipedia.org/wiki/PDF); Digital watermarking - Wikipedia (https://en.wikipedia.org/wiki/Digital_watermarking)

Related tools:

- [Sign a PDF](https://hirantha.me/tools/pdf-sign.md): Draw or type a signature and place it on a document.
- [Organise a PDF](https://hirantha.me/tools/pdf-organise.md): Delete, reorder, and rotate pages in a PDF.