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Watermark PDF

Stamp text across the pages of a PDF — diagonal, straight or tiled, at the opacity you choose. Runs in your browser, so the document is never uploaded.

Runs on your deviceFree, unlimited

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Accepts .pdf · One file at a time · up to 150 MB each "Upload" and "download" here mean your browser reading a file from this device and writing one back to it. Your file is never sent to a server — open your browser's network panel and watch: no request carries your file.

Watermark PDF FAQ

Can I use Chinese, Japanese or Arabic text?

Yes, and that is worth knowing because most tools built the obvious way cannot. A PDF has fourteen built-in fonts and all of them are Latin-only, so a library asked to draw 机密 has no glyph to draw and fails. Rather than embed a multi-megabyte CJK font for one word, we let your own device draw the text — it already has fonts for every script you can type — and place that as the stamp. Anything you can type, including emoji, comes out.

Is a watermark the same as protecting the file?

No, and anyone telling you otherwise is selling something. A watermark is an object drawn over the page; someone with a PDF editor can select it and delete it in a few clicks, on this file or on one from any other tool. What it does is mark provenance and intent — that a copy is a draft, or came from you — which is useful, and it is not access control. Real protection means encryption, which is a different thing and not something we do.

Does the watermark land the right way up on scanned pages?

Yes. This is the detail that catches tools out: PDF drawing coordinates ignore the rotation a page declares, so a stamp placed at the middle of a page a scanner marked sideways comes out sideways too. Every page here is measured in the frame you actually see, and the stamp is counter-rotated to match. Checked on a file whose four pages declare 0, 90, 180 and 270 degrees: all four came out identically placed.

Do bookmarks and form fields survive?

They do. Stamping edits the document you gave us and saves that same document back out, so the outline, the internal links and any fillable form all stay intact — the same reason rotating is safe. The tools that rebuild a document from copied pages, like merging and splitting, keep the bookmarks but lose the internal links.

How much larger does the file get?

Barely. The stamp is rasterised once and embedded once, then referenced by every page it appears on, so a two-page document and a two-hundred-page document pay almost the same cost. Measured: stamping all 33 pages of a 1.1 MB specification added 14 KB. Nothing already in the file is re-encoded, so the pages themselves are untouched.

Why does the stamp soften at very high zoom?

Because it is a picture of text rather than text, which is the price of supporting every script. It is drawn at four times the size it will occupy and scaled down, so at any normal viewing or printing size it is indistinguishable — but zoom far enough past 400% and the edges go soft where real text would stay crisp. Page numbers avoid this by being real text, since digits are covered by the built-in fonts.

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