What font size should I use for a watermark across a full page?

Start with 48 pt for text watermarks. At that size, "DRAFT" or "CONFIDENTIAL" remains readable even when the page is zoomed out to thumbnail view.

Will a diagonal watermark overlap important content?

It usually will. Place the watermark at 30–40% opacity so the underlying text remains readable. For contracts or forms, consider a small footer watermark instead of a full-page diagonal one.

Can I add different watermarks to different pages?

Most free online tools apply one watermark to every page. If you need page-specific marks, you will need desktop software or a script.

Does adding a watermark increase the file size?

A text watermark adds only a few kilobytes. An image watermark, especially a high-resolution PNG or logo, can add 50–200 KB depending on its dimensions.

Free Online Tool

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Add custom text watermarks to PDF pages. Adjust opacity, angle, and position locally in your browser.

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How to Use This Tool

1
Upload the PDF you want to watermark.
2
Enter your watermark text and customize style.
3
Download the watermarked PDF.

Why use sotool?

Text or Logo Watermarks

Add a custom label or upload a transparent PNG logo and adjust opacity and angle.

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Label documents as Draft, Confidential, or Sample before sharing with clients or reviewers.

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Browser-Based

Works on Windows, Mac, Linux, Android, and iOS as long as you have a modern browser.

Frequently Asked Questions

Yes. A text watermark on a white background can be covered with a white rectangle in any PDF editor. Think of it as a visible reminder, not copy protection.

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