PDF Watermark

📖 Tool Introduction

A tool for stamping a text watermark onto every page of a PDF. Type a phrase, set the size, opacity and angle, and one click marks the whole document into a new file.

The mark sits centred on each page and can be tilted at 0, 30, 45 degrees and so on, with the common pattern being a diagonal semi-transparent note such as "Confidential" or "Internal use only". Opacity is best kept low: solid text obscures the body and hurts reading, while somewhere around twenty or thirty percent stays visible without interfering with the content.

A standard built-in font is used, so the file barely grows and no font is fetched over the network. The watermark is genuinely drawn onto page content rather than floating above it, so any reader displays it and it prints too.

Everything runs locally in your browser with no upload. Note that this operation layers onto the source rather than deleting anything, and since output is a new file the original stays intact.

The mark is drawn at the same relative position on every page, so pages of differing sizes show slightly different visual weight, which is most obvious in documents with mixed page sizes. Font size is an absolute value in points, so it looks smaller on a large page and larger on a small one; for documents mixing sizes, pick a middle value or process a few pages first and adjust afterwards.

To be concrete about opacity: ten percent barely affects reading and works as a discreet attribution mark; twenty percent is the default for most situations, visible without getting in the way; thirty-five percent becomes noticeably present and suits confidentiality warnings that need emphasis; fifty percent is already quite loud and is best reserved for drafts or void marks rather than everyday use. On angle, forty-five degrees is the most common diagonal, while zero gives a straight, centred horizontal mark.

Typical uses include stamping a company name or "for reference only" on quotes going out, marking internal documents so a leak can be traced, or putting an author name or "draft" on a sample. Think about what the phrase needs to convey before stamping, because a watermark speaks to whoever holds the file and is harder to overlook than a notice buried in the body text.

✨ Key Features

• Stamps every page at once with no page limit
• Size, opacity, rotation and colour all adjustable
• Standard built-in font, no network fetch and little size growth
• Drawn onto the page itself, visible in any reader and in print
• Output is a new file, leaving the original untouched
• Local browser processing with no server upload

🚀 How to Use

1. Click the upload area to pick a PDF, or drag one in
2. Type the watermark text, such as Confidential
3. Adjust size, opacity, angle and colour
4. Press start and wait for the progress bar
5. Press download to save the watermarked PDF

⚠️ Things to Note

• Watermarks cannot be undone alone: Since output is a new file, start from the original again if you want it removed
• Heavy watermarks hurt reading: Keep opacity low so the body text is not obscured
• Text watermarks only: Image logo watermarks are not supported yet, use text instead
• Very large files hit memory limits: Hundreds of pages process slowly and can exceed memory
• Nothing is kept on a server: Output stays on this device and a refresh means processing again