How to Add a Text Watermark to PDF Documents

When to Watermark a PDF

Watermarks add a visible text overlay to your PDF pages. Common uses include:

• Draft documents — Mark unfinished work with "DRAFT" to prevent premature distribution
• Confidential files — Add "CONFIDENTIAL" or "INTERNAL ONLY" to sensitive documents
• Copyright notices — Overlay your name or company on shared materials
• Document versioning — Mark older versions as "SUPERSEDED" or "ARCHIVED"

How Watermarking Works

PDF Worker adds watermarks by drawing text directly onto each page using the PDF's native drawing capabilities (via pdf-lib). This means:

• Lossless — The original page content is not re-rendered or degraded
• Text stays selectable — Existing text, links, and fonts are fully preserved
• Lightweight — Only adds a small amount of data per page

Important: Watermarks are text-only (image watermarks are not currently supported). The font used is Helvetica.

Customization Options

Option	Range	Notes
Text	Any text	Your watermark message
Font size	12–120 px	Larger for full-page marks, smaller for subtle stamps
Opacity	5–100%	Lower values let page content show through
Color	Any hex color	Match your brand or use standard gray
Position	Diagonal, Center, Top, Bottom	Diagonal places text at -45° across the page

How to Add a Watermark

• Go to PDF Worker's Watermark PDF tool
• Upload your PDF (up to 100 MB)
• Enter your watermark text
• Adjust size, opacity, color, and position
• Click "Add Watermark" and download the result

Watermark vs. Password Protection

Watermarks are a visual deterrent — they discourage unauthorized use but don't prevent copying or editing. If you need actual access control, consider password-protecting your PDF instead. For maximum protection, you can apply both: watermark first, then encrypt.

Tips

• Use low opacity (10–20%) for background watermarks that don't obscure content
• Use diagonal position for watermarks that are hard to crop out
• Test with one page first if you're unsure about sizing — adjust and re-apply
• Keep text short — one or two words work best for readability

Add Watermarks Now

Try PDF Worker's free watermark tool. Your files are processed entirely in your browser — nothing is uploaded to any server.