Add Watermark to PDF — Text Stamp Every Page

The most familiar watermark style is a large, semi-transparent word in a light-grey colour, rotated diagonally across the middle of every page. This style balances two goals: the underlying text remains readable, but the reader is constantly reminded of the document’s status. Our tool defaults to this style (grey, ~48pt, 30% opacity, -30° rotation) but every parameter can be adjusted.

For formal or archival documents, a subtler footer-style watermark (small, black, 50% opacity, no rotation) is more appropriate. For eye-catching draft markers, a large red word at 60% opacity is common. The tool supports all of these, and you can preview the effect on the first page before applying it to the whole file.

This tool focuses on text watermarks because they cover the vast majority of use cases and stay crisp at any zoom. Image watermarks (logos, signatures) are a natural extension we can add later without changing this UI. If you need an image watermark today, one workflow is: create a semi-transparent PNG with your logo, then use JPG-to-PDF (or a merge tool) to combine it as a layered page. For most document-status watermarks, however, text is the right choice — and it is what professional legal and enterprise workflows expect.

Under the hood, we iterate through every page in your PDF, compute the centre of the page (or the corner for footer-style placements), and use pdf-lib’s drawText method to render your text at the specified size, colour, opacity and rotation. Because drawText operates on the page’s content stream, the watermark is a first-class PDF text object — not a bitmap. That is what makes it copy-and-paste compatible and print-friendly.

The original content of each page is left completely untouched. That means removing the watermark later, or comparing the watermarked file against the original, remains straightforward.

A watermark often signals that the underlying document is sensitive — which makes it doubly important not to upload it to a random online service just to add a label. Our client-side pipeline gives you the convenience of an online tool with the safety of a desktop one. Drop the PDF, configure the watermark, apply, download. No file ever leaves your device, and no history is retained.