Add Watermark
Add text watermark to your PDF locally.
Drag & drop files here, or click to select
How to Add Watermark to PDF Online
Select your PDF file from your device.
Choose the text watermark option.
Set the text value (e.g. 'DRAFT').
Adjust the position, font size, rotation angle, margin layout, and opacity level.
Click the Add Watermark button to save your document.
Why Use SonuPDF to Watermark PDFs?
In-Browser Watermarking
Watermark processing runs fully inside your local browser memory. In contrast to online upload products, your document is never stored or processed on a remote server.
Exact Layout Positioning
Place watermarks in nine grid locations or specify exact offset margins to fit your template requirements.
Alpha Opacity Control
Fine-tune transparency levels from 5% to 95% to ensure the watermark is readable but does not obscure main document text.
Standard Font Compatibility
Uses highly compatible system fonts to guarantee the watermark renders correctly on all PDF readers.
Frequently Asked Questions
Yes, all watermarking is executed client-side. We do not upload, review, or store your documents.
Yes, you can change the text string, font size, color palette, rotation degree, and opacity level.
An opacity level between 10% and 20% is typically recommended to keep the watermark subtle without blocking underlying text.
Yes, since the watermark is added as a standard vector/text element in the PDF file structure, it will print with crisp resolution.