What is the difference between a watermark and a stamp?

In PDF terminology, a stamp is typically a visible label placed on a page, while a watermark is usually a semi-transparent diagonal overlay. This tool adds a diagonal semi-transparent text overlay, combining both concepts.

Can I stamp a different label on each page?

Currently the same watermark text is applied to every page. If you need page-specific labels, process the PDF in separate runs.

What font is used for the watermark?

The watermark uses Helvetica Bold, which is a standard PDF font available in all PDF viewers without embedding.

Is there a page limit?

There is no hard page limit. All processing runs locally in your browser tab, so very large PDFs may take a few seconds.

Are my files private?

Yes. All processing runs in your browser. The Content Security Policy on this site blocks all outbound connections at the browser level.

Stamp PDF Pages

Stamp a diagonal text label across every page of your PDF, ideal for marking documents as DRAFT, CONFIDENTIAL, or SAMPLE before sharing. All settings are adjustable and everything runs in your browser.

Drop a PDF here or click to browse

How it works

This tool uses pdf-lib, a pure JavaScript PDF library. It loads your PDF in memory, draws your watermark text diagonally across the centre of each page using the HelveticaBold font at the opacity and size you choose, and downloads the result. Entirely in your browser.

Processing runs in your browser

All processing happens inside your browser tab. pdf-lib applies the watermark entirely in memory, with no network requests.

Related operations

For tagging each page with a numeric label, try PDF page numbers. To bundle watermarked files into one PDF, use merge PDF. For shrinking the marked output, see compress PDF.

Frequently asked questions

What is the difference between a watermark and a stamp?: In PDF terminology, a stamp is typically a visible label placed on a page, while a watermark is usually a semi-transparent diagonal overlay. This tool adds a diagonal semi-transparent text overlay, combining both concepts.
Can I stamp a different label on each page?: Currently the same watermark text is applied to every page. If you need page-specific labels, process the PDF in separate runs.
What font is used for the watermark?: The watermark uses Helvetica Bold, which is a standard PDF font available in all PDF viewers without embedding.
Is there a page limit?: There is no hard page limit. All processing runs locally in your browser tab, so very large PDFs may take a few seconds.
Are my files private?: Yes. All processing runs in your browser. The Content Security Policy on this site blocks all outbound connections at the browser level.

Stamp PDF Pages

How it works

Processing runs in your browser

Related operations

Frequently asked questions

Related tools