What Watermark PDF does
Watermark PDF stamps a text watermark - like "CONFIDENTIAL", "DRAFT" or "SAMPLE" - across every page of a PDF, in a color, size, angle and opacity you choose. It's a quick way to mark a document's status or ownership before sharing it, without opening a full PDF editor.
The watermark is drawn directly onto each page in your browser using a JavaScript PDF library, and the result downloads straight to your device - the original file is never uploaded anywhere.
How to add a watermark to a PDF
- Choose a PDF file - its page count appears once it loads.
- Type your own watermark text, or pick one of the quick presets (CONFIDENTIAL, DRAFT, SAMPLE, DO NOT COPY).
- Adjust the font size, opacity, angle and color to taste - a lower opacity keeps the underlying page readable.
- Select Add watermark & download to save a new copy with the watermark on every page.
Choosing opacity and angle
A diagonal watermark at low opacity (20-35%) is the common choice because it crosses the page without blocking any single line of text for long, and stays legible as a watermark without competing with the document's actual content. A horizontal watermark at higher opacity reads more like a stamp and suits a short word placed where it won't overlap dense text.
What this tool doesn't do
This adds a text watermark only - it doesn't embed a logo or image, and the same watermark (text, size, color, angle) is applied identically to every page rather than positioned per page. For an image watermark or page-by-page placement, a full desktop PDF editor gives more control.
Common uses
- Drafts — marking a document as not yet final before circulating it for feedback.
- Confidential documents — flagging sensitive material before it's shared.
- Sample materials — stamping a preview or sample copy before the paid version is delivered.