Add Watermark
Stamp a custom diagonal text watermark across every page.
Stamp custom diagonal text — like CONFIDENTIAL or DRAFT — across every page, with opacity you control, entirely in your browser.
Stamp a custom diagonal text watermark across every page.
Watermarking is a quick way to label a document before you share it — marking a draft as not-yet-final, stamping a confidential file, or branding a document with your own text. This tool embeds your chosen text diagonally across every page of the PDF using the pdf-lib library, adjusting the opacity so the underlying content stays fully readable underneath.
You control both the text (up to 40 characters, so something like “CONFIDENTIAL”, “DRAFT”, or a company name fits comfortably) and the opacity, from a light 10% for a subtle mark to a bold 80% for something that's hard to miss. The watermark is added to every page in one pass, so there's no need to repeat the process page by page.
Enter your watermark text, adjust the opacity slider to taste, select your PDF, and click Add & Download. The watermarked file downloads immediately with your text stamped diagonally across each page.
No installs, no accounts, and no waiting on server queues. Everything happens locally on your device.
Type up to 40 characters — like CONFIDENTIAL, DRAFT, or a company name.
Choose how bold or subtle the watermark should be, then pick your file.
Your text is stamped diagonally across every page and the file downloads instantly.
The current tool stamps your text diagonally across the center of each page in a neutral gray, which is the standard look for draft and confidentiality watermarks. Opacity is adjustable from 10% (subtle) to 80% (bold).
The watermark is applied at a partial opacity so the page content underneath stays visible and readable. Lower opacity settings make the watermark less intrusive if you're worried about it interfering with text or images.
Since the watermark is drawn as text directly onto the page content, it becomes part of the PDF and isn't designed to be removed afterward — keep an unwatermarked copy of your original file if you might need it later.
No, adding a text watermark only adds a small amount of data to the PDF (a font reference and the drawing instructions), so the file size stays essentially the same as the original.
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