Free browser tool

Add watermark to PDF

Add a text watermark to every PDF page with opacity, angle, and size controls.

Input and settings

How to use

Add watermark to PDF processes your input in the browser, then lets you inspect or download the result.

Choose or paste the input.
Adjust only the options you need.
Run the tool and inspect or download the result.

Input: PDF files and the settings required for this operation
Processing: In-browser

Before using the result

Keep the original PDF for important documents and open the downloaded result to verify it before replacing the original.

A watermark is a visible overlay

The tool places text such as CONFIDENTIAL over each page. It can communicate handling intent, but it is not DRM, password protection, or access control.

A watermark does not technically prevent copying

It may discourage reuse, but it does not enforce permissions. For sensitive documents, treat the watermark as one layer alongside appropriate sharing and access controls.

The built-in PDF font does not support every script

This tool uses standard Helvetica Bold. Text such as Japanese cannot be encoded by that standard font. The tool now catches unsupported text before pdf-lib exposes a low-level font error.

Balance visibility against readability

High opacity can obscure the document, while a very faint mark may be easy to miss. Open a few pages of the saved PDF and check the size, angle, and overlap before distributing it.

Go one level deeper

Review the PDF workflow and common failure points →