PDF guides
How to Add a Watermark to a PDF Online
Watermark PDF stamps a text label or an image across your PDF pages directly in your browser. This guide covers choosing a mode, positioning the watermark, and applying it to all pages or just a range.
Ready to try the tool this guide describes?
Step-by-step watermarking
- Open /tools/watermark-pdf and choose or drop a PDF (up to 25 MB, up to 300 pages).
- Choose Text or Image as the watermark type.
- For text, type the watermark string. For an image, upload a PNG or JPG.
- Pick a position (center or a corner), then adjust opacity, rotation, and size.
- Leave Pages set to All pages, or switch to Custom range and list the pages to stamp.
- Select Add watermark & download.
Text vs image watermarks
A text watermark is quickest for labels like "DRAFT" or "CONFIDENTIAL" — no extra file needed. An image watermark is better for a logo or a stamped signature graphic. Only PNG and JPG images are supported for the image mode.
How the watermark is applied
The watermark is drawn directly onto each existing page rather than rendering pages to images and rebuilding the file, so the original page dimensions and content quality are preserved.
Password-protected PDFs are not supported as input.
Privacy
Watermarking runs locally in your browser using pdf-lib. Your PDF is not uploaded to Looty Tools servers.
How to Watermark a PDF FAQ
- Can I watermark only some pages instead of the whole PDF?
- Yes. Switch Pages to Custom range and list the pages or ranges you want stamped, for example "1-3, 5". Everything else is left untouched.
- What image formats can I use for an image watermark?
- PNG and JPG only. Other formats like GIF or WebP are not currently supported.
- Will the watermark change my PDF page size or quality?
- No. The watermark is drawn on the existing pages, so page dimensions and content quality stay the same.
- Can I make the watermark subtle instead of bold?
- Yes. Lower the opacity slider so the watermark is faint enough not to obscure the underlying content.
- Are my files uploaded when I add a watermark?
- No. Watermarking runs locally in your browser.
Related guides
- Text vs Image WatermarksCompare text and image watermark modes for PDFs — when a word like DRAFT beats a logo stamp, and which image formats each mode supports.
- Watermark Position & OpacityLearn how position, opacity, rotation, and size controls interact when watermarking a PDF, and how to pick settings that stay legible without hiding content.
- How to Protect a PDFAdd a password to a PDF in your browser: choose a password, confirm it, and download an AES-256 encrypted copy that only your password can open.