How to Add a Watermark to a PDF: Text, Position, Opacity and Pages

A watermark is text laid over a page to say something about the document: DRAFT, CONFIDENTIAL, COPY, or a name or date. It does not change the content underneath, and done well it is visible without making the page hard to read. Done badly, it hides the very text people need.

What you can set

The Add Watermark to PDF tool stamps text on your pages in your browser. You control:

• The text. One short phrase works best. Long text must shrink to fit.
• Layout. Place it once in the centre of each page, or repeat it across the page.
• Size. Font size from 16 to 140 points.
• Opacity. From 5 to 100 percent. Lower values are fainter.
• Angle. From 0 to 90 degrees. A diagonal angle (about 45 degrees) is the classic look.
• Colour and weight. Choose a colour and bold or regular.
• Pages. Every page, or a range such as 1-3, 5.

The file is processed in your browser and is not uploaded. Files up to 200 MB are accepted.

Choosing settings that stay readable

The goal is that a reader notices the watermark but can still read through it.

1. Start with low opacity. Between 15 and 30 percent is a good starting point for a dark colour such as grey or red on white pages. Raise it only if the mark is too faint to see.
2. Use a mid-size font. A watermark that fills the page diagonally at around 60 to 100 points usually reads well. A tiny repeated mark is harder to remove but more distracting.
3. Pick a colour that contrasts with both text and background. Mid-grey works on most pages. Avoid black at high opacity.
4. Test on a few pages first. The tool has no live preview, so stamp pages 1-2 with a page range, open the result and check how it looks over tables and images, then run the full file.

Watermarking only some pages

Often only a few pages need a mark, such as the pages of a draft section. Enter ranges the way you would in a print dialog: 1-3, 5 marks pages 1, 2, 3 and 5. Pages you do not list are left untouched, which keeps cover pages and signature pages clean.

Limits of the tool

The watermark uses a standard PDF font, so it supports Latin letters, numbers and common punctuation. Characters from other scripts, and emoji, are rejected with a message rather than being drawn as boxes. Password-protected PDFs must be unlocked first with Unlock PDF.

What a watermark does and does not protect

A visible watermark discourages casual misuse and makes it clear what a document is. It does not stop a determined person: a watermark can be covered, cropped or removed with PDF editing software.

Related steps

• Number the pages with PDF Page Numbers so reviewers can refer to them.
• Combine files first with Merge PDF, then stamp the merged document once.
• Keep the original unmarked file. You cannot cleanly undo a watermark once it is saved.