How to Add a Watermark to a PDF

A watermark is a faint mark repeated across every page. It communicates status — DRAFT, CONFIDENTIAL, DO NOT DISTRIBUTE — or simply carries a brand. Adding one is quick, but a few details separate a professional result from a distracting one.

Choosing the text

Short and unambiguous wins. CONFIDENTIAL, DRAFT, © 2026 Acme Ltd. A watermark is not the place for a sentence; long text either overlaps itself diagonally or becomes unreadable at low opacity.

Getting the opacity right

The mark should be noticeable but not fight with the content. Practical ranges:

• 8–15% — subtle, standard for confidential documents that still need to be read comfortably.
• 20–35% — clearly visible, appropriate for draft files where you genuinely want the reader to notice.
• Above 40% — usually too heavy unless the document is meant to be obviously a specimen.

Check it on the busiest page, not the title page. A watermark that disappears over a photo and shouts over white space looks accidental.

Angle and colour

A 45° diagonal is the conventional choice because it crosses the text without sitting parallel to any line of type. Horizontal watermarks work for a single centred mark on cover pages. For colour, grey is the safe default; coloured marks (red for confidential, blue for internal) carry meaning but reproduce poorly on black-and-white printers — red at 15% opacity prints as barely-there pink.

Limitations worth knowing

• Watermarks are not security. Anyone with a PDF editor can remove one. Use password protection if you actually need to control access.
• Scanned pages accept them fine. The mark is drawn on top, so it works whether or not the page has a text layer.
• Print placement shifts. If the document will be printed with scaling ("fit to page"), a bottom-corner mark may move; centre marks are more robust.

Try it now: Watermark PDF · Page Numbers