PDF Stamp - Add Watermarks & Page Numbers to PDFs Online

How to use this tool

Upload your PDF. Drop a PDF onto the upload area or click to browse for a file.
Enable the overlays you need. Tick "Watermark" to stamp text like CONFIDENTIAL or DRAFT, "Page numbers" to number the pages, or both.
Configure and preview. Choose a text preset or enter your own label, then adjust color, font size, opacity, position, rotation, and numbering format. Every page thumbnail shows a live preview of both overlays.
Apply and download. Click Apply. Both overlays are drawn in a single pass and the stamped PDF downloads to your device.

Watermarks and page numbers in one pass

A watermark and a page number are the same operation under the hood: text drawn on top of every page at a chosen position. This tool exposes both as independent overlays with a shared live preview - enable either one alone, or both together, and download a single stamped PDF. The classic combination of "CONFIDENTIAL" diagonally across the page plus "Page N of Total" at the bottom takes one upload and one click instead of a round-trip through two separate tools. Everything runs locally using pdf-lib; nothing is uploaded.

Watermark options

Type any text up to 200 characters or choose a preset such as "DRAFT" or "DO NOT COPY". Set its color, font size (8-144 pt), opacity (5-100%), position, and rotation (-90 to 90 degrees). The diagonal placement starts at 45 degrees across the page centre; other positions start at 0 degrees. Keep opacity around 20-30% so the underlying content stays readable, and use the page thumbnails to check the color and placement before downloading.

Page numbering options

Choose one of six positions (top or bottom; left, centre, or right), a format (plain 1, 1 / 10, Page 1, or Page 1 of 10), the font size, and the starting number. A custom start is handy when the file is a chapter extracted from a longer work and needs to continue that document's numbering, or when a cover page means numbering should begin at 0.

How the overlay is drawn

Both overlays are drawn with the built-in Helvetica font, so no font data needs embedding and the output file barely grows. The text is added on top of the existing page content as a normal PDF text object, so it prints and remains after ordinary re-saving. Existing content is not re-encoded, so there is no image quality loss. A watermark is only a visible label: a person with PDF editing software can change or remove it, and it does not encrypt the file or authenticate its contents.

Limitations to know about

Encrypted PDFs must be unlocked before stamping. The watermark applies the same position and size on every page; a page that is much smaller than the rest may clip a very large watermark, so check the preview when your document mixes page sizes. If a page already carries a visual page number, the new numbers are drawn over the page as-is - pick a different corner to avoid overlap.

Frequently asked questions

Are my PDFs uploaded to a server?

No. All processing is done locally in your browser using pdf-lib. Your files never leave your device.

Can I add a watermark and page numbers at the same time?

Yes - that is the point of this tool. Enable both overlays, configure each independently, and they are applied together in a single pass with one download.

Can I control the opacity of the watermark?

Yes. The opacity slider goes from 5% (nearly invisible) to 100% (fully opaque). Around 20-30% is typical for background watermarks that keep the content readable.

Can I choose the watermark color and angle?

Yes. Pick any solid color and rotate the watermark from -90 to 90 degrees. The diagonal position starts at 45 degrees, while other positions start at 0 degrees.

What page-number formats are available?

Plain numbers (1, 2 …), fractions (1 / 10), "Page N", or "Page N of Total". You can also set the starting number, useful when the PDF has front matter.

Are the overlays applied to all pages?

Yes. The watermark is drawn in the same position on every page, and page numbers increment per page from your chosen starting number.

What font is used?

Helvetica, a standard built-in PDF font available in all PDF readers without embedding - so the file size barely grows.

Does a watermark prevent copying or editing?

No. A watermark is a visible text overlay and can be changed or removed with PDF editing software. It is not encryption, a digital signature, or access control.