Add watermark to PDF
Stamp a custom text or image watermark across every page. Control the opacity, rotation and position to get exactly the look you need — processed privately in your browser.
or drop files here
Tip: select a single file.
How to use Add Watermark
- 1Click "Select PDF file" and choose the PDF you want to watermark.
- 2Type your watermark text (or upload an image), then set opacity, size, and position.
- 3Click Add Watermark. The stamped PDF is created locally and downloaded.
Why use PDF Lab
- Stamp text or image watermarks across any or all pages.
- Files stay on your device — nothing is uploaded to any server.
- No account, no signup, no watermark on the output.
- Free to use with no per-file limits beyond your device's memory.
- Works on desktop and mobile browsers, including offline after first load.
- Adjust opacity, rotation, and position for a professional result.
- Useful for branding drafts or marking documents as confidential.
Your file never leaves your browser
Add Watermark runs entirely on your device using pdf-lib and pdf.js — both self-hosted by PDF Lab, so no third-party CDN sees your traffic. There is no upload, no account, no log of your file.
How browser-based PDF processing works →Add Watermark — questions
- No. Every operation runs in your browser using JavaScript. Your file is loaded into your browser's memory, processed, and a result is saved to your device. Nothing is sent over the network.
- No. Because the processing happens in your browser, neither PDF Lab nor any third party has access to the file contents. You can verify this by opening your browser's network tab while using the tools — no file data is transmitted.
- There is no enforced limit, but performance depends on your device's memory. Most modern browsers comfortably handle PDFs up to about 100 MB. Very large files may slow down your browser tab.
Are my files uploaded to your server?+
Can PDF Lab see the contents of my files?+
Are there file size limits?+
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