How it works
The PDF Watermark tool overlays a text or image watermark on every page of a PDF document — with full control over opacity, position, size, rotation, and font. The watermark is embedded in the PDF's page content streams, not just a visual overlay, so it appears on every viewer and print.
Watermarking PDFs is standard practice for draft documents ("DRAFT", "CONFIDENTIAL", "FOR REVIEW ONLY"), client preview copies ("SAMPLE — NOT FOR DISTRIBUTION"), legal documents ("COPY"), and branded reports. The watermark signals the document's status and discourages unauthorized distribution.
How to use it: upload your PDF. Choose text or image watermark: - Text: type your watermark text, select font, size, color, opacity (20–60% recommended), angle (usually 30–45° diagonal), and position (center, all pages, first page only) - Image: upload a PNG logo with transparent background, set scale and opacity
The watermark is applied to every page (or a selected page range) using pdf-lib's content stream manipulation.
Diagonal placement: a diagonal watermark (30–45° rotation, centered) covering most of the page is the hardest to crop away and the most effective at marking the document's status. Corner watermarks are easily cropped; centered diagonal watermarks are the industry standard.
Privacy: watermark application runs in the browser using pdf-lib. Your PDF is never uploaded.
Frequently Asked Questions
- 20–40% opacity is the standard range for draft and preview watermarks. At 30%, the watermark is clearly legible on white or light areas without significantly obscuring the document content. For decorative or brand watermarks intended to be noticed, 50–60% is more visible.
- Diagonal placement centered on the page is recommended for draft marks like 'CONFIDENTIAL' or 'DRAFT'. It covers the maximum page area and cannot be cropped from a single corner. A diagonal text repeated across the whole page (tiled mode) is the strongest deterrent.
- Yes. Set the page range to 'First page only'. This is useful for cover page branding where subsequent pages don't need the mark, or for 'SAMPLE' watermarks on title pages.
- Yes. Unlike screen-only watermarks (CSS overlays), this tool embeds the watermark into the PDF content stream. It prints on every printer and shows in every PDF viewer — it cannot be hidden by the viewer.