Watermark a PDF

What is a PDF watermark?

A PDF watermark is text drawn on top of every page of a document, usually to mark its status or its owner: DRAFT, CONFIDENTIAL, SAMPLE, or a company or person's name. This tool lets you watermark a PDF for free by adding that text yourself, choosing the size, angle, opacity and colour, and downloading the result.

Drop a PDF onto the page or click to choose one. Nothing is uploaded anywhere — the file is opened and rewritten inside your browser tab, and it never leaves your device. The watermark text defaults to DRAFT but can be anything you type, and it is centred on every page of the output.

How to add a watermark to a PDF

1. Add your PDF and type the watermark text. Drop the file onto the page or click to choose it, then replace DRAFT with whatever text you want, such as CONFIDENTIAL or a name.
2. Set the size, angle, opacity and colour. Make it bold if you like, pick 0, 45, -45 or 90 degrees, adjust how transparent it is as a percentage, and choose a colour swatch.
3. Download the watermarked PDF. The page count and output size are shown next to the download button, so you can confirm the file before you use it.

A watermark is a label, not a lock

A watermark drawn onto a page is a label, not a lock. Once it's drawn, it becomes ordinary page content, the same kind of content as the text underneath it, which means anyone with a PDF editor can select the watermark and delete it. A tool that presents watermarking as protection is selling a feeling, not a fact.

That doesn't make it useless — it makes it a specific tool for a specific job. A watermark is genuinely useful for marking a document as a draft while it's in progress, for asserting authorship on something you're sharing, or for making a leaked copy embarrassing and traceable to circulate. What it does not do is stop anyone determined from removing it or from copying the content underneath. If you need a document that cannot be edited, a watermark is the wrong tool; if you need a document that visibly says what it is, it's exactly right.

What the text can say, and rotated pages

The watermark is drawn using the PDF's standard fonts, Helvetica and Helvetica-Bold, which every PDF reader already has built in — no font file needs to be attached to your file. We tested every one of the 65,536 code points in the Basic Multilingual Plane against these fonts, and exactly 218 of them, across 18 contiguous ranges, can be drawn. That set is ASCII, the accented letters of Latin-1, and a handful of typographic extras like the euro sign, curly quotes, dashes and the trademark sign. The regular and bold faces accept exactly the same 218 characters.

Arabic, Chinese, Japanese, Cyrillic, Greek and emoji cannot be drawn at all with these fonts. Embedding a font that covered those scripts would mean attaching a font file to every single output, which is exactly the kind of payload this site avoids. Rather than fail on you unexpectedly or silently drop characters, the tool tells you the moment you type something it can't draw, naming the specific character that's the problem while you're still typing, so you can swap it out before you download anything.

Rotated pages are handled properly. A PDF page can carry a rotation that readers apply when displaying it, while the underlying content stays in its original position — so the centre a reader actually sees isn't the centre of the page's raw coordinates. This tool computes the centre in the space you see on screen and maps it back, and it measures from the CropBox, which is what readers display, rather than the MediaBox. Whatever angle you choose is applied on top of the page's own rotation, so a page that arrived rotated stays rotated and your watermark still ends up where you expect it.

The centring is exact rather than eyeballed: it was checked in closed form, by confirming that the centroid of the rotated text box lands precisely on the page centre at every angle tested. Opacity is a real PDF graphics-state alpha rather than a lighter colour, verified by reading the value back out of the finished file. And because no font program is added, the watermark costs only about 250 bytes per page.

Why is it free?

Everything happens inside your browser tab — opening the PDF, drawing the watermark, and rewriting the file — so there's no server cost to running this tool and nothing of yours to upload. There's no account to create and no watermark of ours added to your file beyond the one you asked for.