How this tool works

Watermark PDF: a practical guide

Draws your text across each page using the chosen font size, angle and opacity. Zero opacity is accepted as zero; values are not silently replaced.

Steps to use this tool

Select a PDF and enter watermark text.
Set opacity, angle and font size.
Generate the copy and inspect legibility across pages.

Tested example — 19 October 2026

The sample embeds the user-entered watermark MY DRAFT in the output text.

Selected sample: sample.pdf (2421 bytes, 2 pages).

Measured output: sample-watermark.pdf — 6894 bytes; 2 PDF pages.

Sample settings:

{
  "text": "MY DRAFT",
  "opacity": 0,
  "rotation": 0
}

The sample embeds the user-entered watermark MY DRAFT in the output text. — Page 1 rendered from the actual automated sample PDF output; this is not a browser screenshot.

Test environment: Node + native canvas + actual site-ui.js form integration in LinkeDOM Representative sample; inspect your own output.

Check the result

Read small source text beneath the watermark at the intended viewing size. Inspect more than one page to confirm the text and angle fit the document.

Files and privacy

The public tool processes selected documents in your browser. It does not send document bytes to a conversion server. The page and its bundled libraries still download from this website. Keep the original, use an up-to-date browser and inspect your output before sharing it. See the privacy policy for hosting and support information.

If processing fails

If a faint mark is hard to see, adjust opacity within 0 to 1. A font error requires changing unsupported characters rather than repeatedly submitting the same wording.

Implementation notes and sample evidence updated 2026-10-19. These notes describe the supported operation and its limits.

Check the local-processing claim in your browser’s Network panel.

Watermark PDF