Watermark PDF
Add a diagonal text watermark like CONFIDENTIAL or DRAFT to every PDF page — set opacity, size and color. Free and private, in your browser.
About the Watermark PDF
Stamp a diagonal text watermark across every page of a PDF — CONFIDENTIAL, DRAFT, PAID, SAMPLE or any text you type. The watermark is drawn at 45 degrees through the center of each page in gray, red or blue, with an opacity slider so it stays clearly visible without obscuring the underlying content.
Watermarks communicate a document's status at a glance and discourage misuse: legal teams mark drafts before circulation, accountants stamp PAID on invoices, and HR departments label internal policies CONFIDENTIAL. Because the text becomes part of each page's content, it survives printing, screenshots and re-saving.
Everything happens in your browser with the pdf-lib library — the document is never uploaded, so the very files most worth watermarking (contracts, financials, unpublished work) stay completely private. Download the watermarked copy in seconds, free and without limits.
How to Use the Watermark PDF
- 1Upload the PDF you want to watermark.
- 2Type the watermark text — CONFIDENTIAL is pre-filled, but any text works.
- 3Set the opacity, font size and color (gray, red or blue).
- 4Click Add Watermark and download the stamped PDF.
Frequently Asked Questions
How do I add a CONFIDENTIAL watermark to a PDF for free?
Upload the PDF, keep the pre-filled CONFIDENTIAL text (or type your own), choose a color and opacity, and click Add Watermark. The word is stamped diagonally across the center of every page and the finished file downloads immediately. The tool is free, adds no branding of its own and has no page or file limits.
What opacity should a watermark have?
Around 20–30% works for most documents: the watermark is unmistakable but body text underneath remains fully readable. Use lower values (10–15%) for dense, text-heavy pages, and higher ones (40–60%) when the watermark must dominate — for example SAMPLE on documents you don't want reused. The slider lets you regenerate until it looks right.
Can the watermark be removed later?
The watermark is drawn into the page content rather than added as a removable annotation, so it survives printing, flattening and most editing. Determined users with professional PDF editors could still remove it, so treat a watermark as a strong deterrent and status label, not as tamper-proof security — for that, combine it with password protection.
Does the watermark appear on every page?
Yes. The text is stamped diagonally through the center of each page in the document, automatically adapting to each page's size and orientation — mixed portrait and landscape pages all get a properly centered 45-degree watermark. There is no limit on the number of pages.
Is my document uploaded when I watermark it?
No. The PDF is processed entirely on your device in the browser — it is never transmitted to a server, stored or logged. That privacy matters most for exactly the documents people watermark: unsigned contracts, financial statements, manuscripts and internal reports.