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Add Watermark to PDF

Places a diagonal text watermark on every page. Works with any language and emoji.

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Private by design — this tool never uploads your files anywhere. Everything runs inside your browser, and the finished file is saved straight to your device.

Other conversion sites upload your file to a server, process it there, and say they delete it after a while. Until that happens, your file sits on someone else’s server. Here there is no upload step at all. The more sensitive the file — contracts, ID scans, medical records — the more that difference matters. See how to verify it →

Stamp “Confidential” or a name across every page to trace a leak

When a draft or a submitted copy must not be reused elsewhere, a phrase laid across every page leaves a trace of where it came from. This tool renders the text you type as a semi-transparent diagonal watermark, places it on every page and saves a new PDF. Any script, including accents, CJK and emoji, comes out as typed, and the file is never uploaded.

A closer look

The watermark is not inserted as PDF text. It is drawn in a bold font on a browser canvas, tilted about 36 degrees, turned into a transparent PNG and painted onto each page. Because it is an image, characters that no embedded PDF font could show, such as Korean or emoji, come out intact; the flip side is that the watermark text is not found by search or text selection. The colour is fixed grey. The opacity slider runs from 8 to 60, and the default of 18 is a light stamp that barely affects readability.

With “Tile across page” off, one large stamp sized at 85% of the page’s shorter side goes in the centre. With it on, the stamp repeats in a grid spaced at 42% of the page width, so any cropped fragment still carries the text. A long phrase is shrunk to fit inside a square, so the letters get small; around ten characters keeps it legible. The tool only adds watermarks and cannot remove one that is already there. A watermark is a layer over the document, and full removal is generally not possible.

How to use it

When it helps

Mark draftsStamp “DRAFT” or “For review” so a working copy is not mistaken for the final and sent out.
One copy per recipientPut each recipient’s name on the copy you send them so you can tell which copy leaked.
Protect proofsLay your name over design proofs or a photo portfolio to discourage use before approval.
Course handoutsTile “Do not redistribute” over lecture notes to discourage screenshots and resharing.

Common snags

The watermark is too faint to see.Move the Opacity slider to the right; 60 is the strongest. On scans with a greyish background the stamp is easily lost, so 30 or higher works better there.
It covers the text and makes the page hard to read.Lower the opacity or turn Tile across page off so only one central stamp is placed. The watermark is painted over the content, so a strong stamp will hide it.
My long sentence came out tiny.The whole phrase is scaled to fit inside a square. Keep to the key words and put any detail in a separate note.
I only want it on some pages.The tool always stamps every page. Separate the pages you need with Split PDF, watermark them, and rejoin with Merge PDF.

Tip Before sending, open the result and check a page heavy with tables or images to make sure the stamp does not obscure anything. The right opacity differs from one document to the next.

FAQ

Will special characters or non-Latin text break?

No. The watermark is rendered as an image before being placed, so every script — accents, CJK, emoji — comes out exactly as typed.

Can this remove a watermark?

No, it only adds them. A watermark is a layer stamped over the document, and fully removing one is generally not possible.