PDF Watermark
Add a diagonal text watermark to a PDF.
Your files stay on your device
This tool processes everything locally in your browser. Nothing is uploaded to a server.
📝 About PDF Watermark
PDF Watermark stamps a diagonal line of text across the center of every page. Watermarks are a simple way to mark a document’s status, such as DRAFT or CONFIDENTIAL, or to discourage a shared copy from being reused, for instance by writing “SAMPLE” across a portfolio or a quote you send to clients.
Type your text (CONFIDENTIAL is filled in by default) and set the opacity between 5% and 60%. The text is drawn in a bold gray font at a 45° angle, centered on each page. A lower opacity of around 15–25% keeps the underlying content easy to read while the mark remains clearly visible; higher values make the watermark harder to ignore but can get in the way of reading.
One important limit: the watermark uses a standard built-in PDF font that only supports basic Latin characters, so use English letters, numbers and common symbols. Korean, Japanese or Chinese text won’t work. Keep in mind that a text watermark deters casual reuse but can be removed with PDF editing software. Processing happens entirely in your browser; your file is not uploaded.
📘 How to use
- 1
Upload a PDF
Drop or select the PDF you want to watermark.
- 2
Set text and opacity
Enter the watermark text in English and adjust the opacity slider.
- 3
Add and download
Click Add watermark to download the file ending in “-watermarked.pdf”.
❓ FAQ
Can I use Korean or other non-Latin text?
No. The watermark uses a standard PDF font that supports only basic Latin characters, so use English letters, numbers and common symbols.
Can I change the position, color or size?
The watermark is always gray, 45° diagonal and centered on each page at a fixed size. You can change only the text and opacity.
Can someone remove the watermark?
It’s added as a separate text layer, so someone with PDF editing software could remove it. It works best as a visible deterrent, not as strong protection.