Add a Watermark to a PDF
Stamp text such as CONFIDENTIAL across every page.
🔒 Your file is processed inside your browser. It is never uploaded or saved.
What is Watermark PDF?
A watermark tells readers how to treat a document: draft, confidential, copy or paid. This tool writes your text diagonally across the middle of every page, in a size and strength you choose, and saves a new PDF.
How to watermark a PDF
- Upload the PDF.
- Type the watermark text, such as CONFIDENTIAL.
- Choose the size (small, medium or large) and strength (light, medium or strong).
- Press Start and download the stamped file.
When Watermark PDF is useful
Drafts
Mark early versions so nobody mistakes them for final copies.
Confidential files
Remind recipients that a document is private.
Proofs
Stamp samples that you share before payment.
Tips for better results
Use Light for long text so the document remains readable. A watermark is a visual mark and can be cropped or covered by someone with editing tools, so it does not secure a document. Use English letters and numbers.
Good to know before you start
The stamp is drawn at 45 degrees across the centre of every page in bold grey letters. Size controls how large the text is, and strength controls how opaque it is, so Light leaves the page readable and Strong makes the mark obvious. Short words work best: CONFIDENTIAL, DRAFT, COPY or SAMPLE fit the page, while long phrases may extend beyond the edges. The watermark is part of the page content, so it also prints. If you want a mark that cannot easily be removed, flatten the pages into pictures afterwards by compressing the file, which merges the watermark into the page image.
Why use PDFToolkit
When you watermark a PDF with PDFToolkit, the work stays on your own device. Your contracts, ID scans and invoices are processed in the browser and are never sent to a server.
- Private: no upload, nothing saved.
- Free: no sign-up, no daily limit and no watermark.
- Fast: no waiting for files to travel over the internet.
- Everywhere: Windows, Mac, Linux, Android and iPhone.
Frequently asked questions
Can I use a logo?
No. This tool adds text only.
Is the watermark on every page?
Yes.
Can the watermark be removed?
It is part of the page content. A determined person with editing software may remove it, so do not rely on it for security.
Is the file uploaded?
No.