Add Watermark

Watermarking your PDF documents is an effective way to indicate their status, protect confidentiality, or assert ownership. Our Add Watermark tool stamps diagonal text across every page at an optimal 30% opacity, with the text size automatically scaled to 10% of the page dimensions.

Common use cases include marking drafts as "CONFIDENTIAL" or "DRAFT," adding copyright notices to creative works, or labeling client deliverables with project names. The diagonal placement ensures the watermark is visible but does not obscure the underlying content.

The watermark is rendered client-side using pdf-lib with bold Helvetica font and red coloring. Your document never leaves your device, ensuring complete privacy. The tool is free with no registration or file size limits.