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Watermark PDF

Add a custom text watermark — like "CONFIDENTIAL" or "DRAFT" — across every page of your PDF. Choose the color, size, opacity and rotation. This tool stamps text watermarks only. Everything runs in your browser, so your file never leaves your device.

Your PDF is processed entirely in your browser with JavaScript — the file never leaves your device and is never uploaded to any server.

Understanding the Watermark PDF

Watermark PDF is a free, browser-based tool that stamps a custom text watermark — such as CONFIDENTIAL, DRAFT, or a company name — across every page of a PDF. You control the text, font size, color, opacity, and rotation angle, then download a new watermarked copy. It is ideal for legal teams, freelancers, students, and anyone sharing draft or sensitive documents who wants visible ownership or status marks. Because all processing runs entirely in your browser with JavaScript, your PDF is never uploaded to a server and never leaves your device, making it safe for confidential files.

How it works

When you click Apply watermark, the tool reads your PDF into memory as bytes and loads it with the pdf-lib library directly in the browser. It embeds the Helvetica-Bold standard font and converts your chosen hex color into red, green, and blue values scaled from 0 to 1. It then loops through every page, measures the rendered width of your text at the chosen font size, and draws the text near the page center at the opacity and rotation you set. Finally it saves the modified document to new bytes, wraps them in a Blob, and triggers a download as watermarked.pdf. No network request is ever made.

Worked example

Suppose you upload a 5-page contract and type CONFIDENTIAL as the text, set font size 48, opacity 0.3 (30%), rotation 45 degrees, and color #ff0000 (red). The tool measures the text width at 48pt, then on each of the 5 pages draws a translucent red CONFIDENTIAL tilted 45 degrees through the middle of the page. After a moment a file named watermarked.pdf downloads, with the original pages intact underneath the diagonal red stamp.

Tips & common mistakes

  • Use a low opacity such as 0.2-0.35 so the watermark is visible but does not obscure the underlying text.
  • A 45-degree rotation gives the classic diagonal stamp; use 0 degrees for a flat, horizontal label.
  • Larger font sizes (40-72) read better as full-page watermarks; smaller sizes suit footers or corners.
  • Pick a color that contrasts with your document — red or gray works well on black-on-white pages.
  • The tool stamps text only; if you need an image or logo watermark, add it to the PDF before uploading.
  • Encrypted or password-protected PDFs cannot be loaded — remove the protection first, then watermark.

Related tools

PDF MergeCombine multiple PDF files into one, reordering pages before merging.PDF SplitExtract specific pages from a PDF or split it into individual files.PDF CompressReduce PDF file size by removing metadata and overhead.JPG to PDF ConverterConvert JPG and PNG images into a single PDF, in order, in your browser.

How to Watermark a PDF

  1. 1Upload or drag in your PDF file.
  2. 2Type your watermark text and adjust size, color, opacity and rotation.
  3. 3Click Apply watermark — your stamped PDF downloads automatically.

Frequently Asked Questions

Is my PDF uploaded anywhere?

No. The watermark is applied entirely in your browser using a JavaScript PDF library. Your document never leaves your device and is not sent to any server.

Does it watermark every page?

Yes. The chosen text, color, size, opacity and rotation are stamped onto every page of the PDF automatically — there is nothing extra to configure.

Can I use an image or logo as the watermark?

Not yet. This tool stamps text watermarks only. You can fully control the text, font size, color, opacity and angle to suit most needs.