How to Watermark PDFs Online
Protect your sensitive documents and business forms by applying a highly visible watermark across all of your PDF pages. Our free online PDF watermarking tool lets you stamp custom text diagonally over your documents to declare ownership or warn against unauthorized distribution.
Applying the Stamp
Applying a watermark takes just three simple steps:
- Upload a File: Select the PDF document you want to stamp from your device or drop it into the upload box.
- Enter Text: Type in the phrase you want to use for the watermark. Common examples include "CONFIDENTIAL", "DRAFT", or "DO NOT DISTRIBUTE".
- Process and Save: Click the "Add Watermark" button. Your custom text will be overlaid diagonally on every single page at a low opacity, and the document will download instantly.
Is the Watermark Permanent?
Yes, the watermark applied by our tool interacts with the PDF's core instruction set to draw text directly onto the page. When you apply a watermark here, it is embedded into the stream of every page. This prevents casual users from simply dragging and deleting the watermark within a basic viewer, keeping your "CONFIDENTIAL" warnings secure.
Why Use Our Watermark Tool?
100% Private Processing
Unlike other PDF tools that force you to upload your sensitive documents to a remote server, our tool works entirely within your web browser using client-side JavaScript. The files remain strictly local on your device and are never transmitted over the internet.
Auto-Scaling Text
You don't need to worry about font sizes or confusing margins. Our algorithm calculates the width of your document and scales your watermark phrase up perfectly so that it acts as an unmissable diagonal banner across the page.
No Hidden Limitations
We don't limit how many times you can use our tool, nor do we artificially restrict the file size to try and force you into a paid subscription. You can freely stamp massive, 500-page scanned documents completely free of charge.
Instant Downloads
Due to our client-side architecture, the processing is nearly instantaneous. You don't have to wait in queues for a cloud server or endure slow upload/download periods—your stamped file is ready right away.