Watermark PDF

How Watermark PDF works

Type the text and it is drawn in grey across the middle of every page, either diagonally from corner to corner or straight across. Size and opacity are yours to set: at the default 30 percent the page stays easy to read, while higher values make the mark harder to ignore.

The watermark is added to the page content in DejaVu Sans, a font that covers Latin, Greek, Cyrillic and many other alphabets, so names with accents come out correctly. The rest of the page is untouched: text stays selectable and images keep their quality.

A text watermark marks a document; it does not lock it. Someone with a PDF editor could remove it. For real protection, combine it with Protect PDF. Everything is done by pdf-lib inside this tab, so drafts and confidential documents are never uploaded.

The watermarked file keeps its name with -watermarked added, so you can keep the clean original. Because the mark is drawn on top of the page, it covers text and pictures alike without hiding them, and it appears in print as well as on screen. Several PDFs can be watermarked in one go with the same text, which suits labelling a set of documents sent to one person. For different recipients, run the tool once per person with their name in the text, which makes any leaked copy traceable to its source.

Watermark PDF options explained

When to use it

Watermark documents to mark drafts that should not be circulated as final, to label copies sent to different people, to discourage reuse of a portfolio or quote, or to make it clear that a scan of an ID was supplied only for one purpose.

Adding the purpose and date to ID scans, such as "For ACME tenancy check only, 2026", makes a copy much less useful to anyone who misuses it.

About these PDF tools

The page tools, from merge and split to crop, resize, watermark and page numbers, use pdf-lib, an open-source JavaScript library that reads the structure of a PDF and writes a new one. Because it works on the page objects themselves rather than on pictures of them, text stays text, fonts stay embedded and vector drawings stay sharp, and nothing is added to your pages that you did not ask for. None of these tools edit what is already printed on a page: to change wording or fill a form, use a PDF editor. Password-protected PDFs must be unlocked first, since the pages cannot be read without the password. Every tool works on a copy, so the file on your device is never changed.

Watermark PDF troubleshooting

"Type the watermark text"

The text box is empty. Type the words you want on the page.

The mark is sideways on some pages

Pages stored rotated inside the PDF get the mark in their stored direction. Rotate those pages with Rotate PDF first.

Some characters show as boxes

Chinese, Japanese, Korean and Indic scripts are not in the embedded font. Use Latin, Greek or Cyrillic text.

How to use Watermark PDF, step by step

1. Press "Choose PDF files" or drag PDFs onto the box.
2. Set the options if you need to; the defaults suit most uses.
3. Press "Add watermark". The work happens on your device.
4. Save the result with its download button.

Is it safe to do this online?

With most online tools, "online" means your file is uploaded to a company's server, processed there and kept for a while before it is deleted. Here it is not. The page downloads the tool's code to your browser, and your file is read and processed inside the tab on your own device. It is never sent to TapToConvert or anyone else.

You can check this yourself: once the page and its engine have loaded, turn off Wi-Fi and the tool still works. That also means there is no queue, no daily limit and no file size cap set by a server; the only limit is the memory your browser gives a single tab.