Add Watermark to PDF
Add a text watermark with control over angle, opacity, grey level and whether it draws over or under the page content. Nothing on the page is flattened.
Tool workspace
Nothing is uploaded. Files are read in this tab and stay on your machine.
Add a text watermark
Save your download before you leave the page — it exists only in this tab.
How do I add a watermark to a PDF?
Select one PDF and check the page count shown.
Enter the watermark text, then set its size, angle, opacity, grey level and whether it draws over or under the page.
Select Add watermark and save the result before leaving the page.
How is a watermark added without flattening the PDF?
Add a text watermark to a PDF, with control over angle, opacity, grey level and whether it sits over or under the page content. Nothing on the page is flattened.
The watermark is a separate set of drawing instructions, drawn either before or after the page's own content depending on which you choose. Reduced opacity is a setting the PDF reader applies as it draws the mark, not a change to any pixels, so no page content is rasterised, altered or flattened. Drawn over, the mark is always visible; drawn under, it is hidden wherever the page paints an opaque background, which on a scanned sheet is everywhere.
How Xenmark makes it easy to add a watermark to a PDF
A text mark centred on each page
Type the wording, add an optional smaller second line, and set the angle. The mark is centred on the page, at 45 degrees unless you change it; positive angles turn anticlockwise.
Nothing leaves your machine
Nothing is uploaded. Files are read in this tab and processed in memory, with no account and no server for them to go to.
On top of the drawing or beneath it
Draw the mark over the content so it always shows, or under it for pages with a transparent background. The page is not flattened either way.
Opacity and grey level under your control
Set the mark anywhere from faint to fully solid and pick any grey from black to white, without rasterising the page beneath it.
Mark only the pages you name
Watermark the whole document, or enter pages such as 3-8 and leave every other page in the file unmarked.
Nothing to install
It runs in the browser you already have. There is no plug-in, no desktop application and no sign-up to get through first.
Limitations
What this tool does not do, stated up front.
A watermark is a visual mark, not a protection measure. It can be removed by anyone with a PDF editor and is not a substitute for document control.
Watermarks are text only, set in a standard PDF font; images and logos cannot be used. A character that font cannot write is refused rather than swapped for a look-alike, because CONF?DENTIAL across every page would be worse than no watermark.
A digitally signed PDF will no longer validate once a watermark is added; keep the signed original.
Questions
Should the watermark go over or under the page?
Over, in almost every case. Under only works on pages with a transparent background; a scanned sheet paints white everywhere and would hide the mark completely.
Does reducing opacity damage the page?
No. The opacity is a drawing setting that applies to the watermark alone. The page content is copied unchanged and nothing is flattened.
Can a watermark stop someone copying the document?
No. It marks the document visually. Anyone with a PDF editor can remove it, so treat it as labelling rather than as protection.
Why did Xenmark build a free watermark tool?
Xenmark AS is a Norwegian software company building browser-based drawing review tools for owners, consultants, operators and other teams that receive and review technical drawings. Those teams handle PDFs every day, and not every file should be sent to a website just to merge, split or check it — a tender document, a client’s drawing set, a revision that is not released yet. So these everyday tools are free and run entirely in your browser: no account, no upload step, and no server ever receives the file. You can check that yourself — open your browser’s network tab, stamp DRAFT across a file, and watch nothing leave. What this tool cannot do is listed under Limitations above.
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