Watermark PDF
Stamp CONFIDENTIAL, DRAFT, your name or a logo across every page — size, angle, opacity and colour under your control, all in your browser.
How to Watermark a PDF in 3 Steps
Drop a PDF
The first page shows on the left so you can judge the result against it.
Choose the Watermark
Type the text, or switch to Image and pick a PNG logo. Set size, opacity, angle and colour in Settings, and choose centred or tiled. Leave Pages blank for every page, or enter a range like 2-5.
Apply & Download
Click Apply, check the preview on the right, tweak and re-apply as often as you like, then download.
Watermark PDF — Frequently Asked Questions
Is the watermark permanent?
It is drawn onto the page content, so it survives printing, copying pages into other PDFs and most viewers. It is not DRM — a determined person with editing software can still remove page content. For a security measure use Protect PDF as well.
Why does my text come out as boxes or fail?
The built-in Helvetica font covers Latin characters only. For other scripts or special symbols, make a PNG of the text (e.g. with the OG Image Generator) and use Image mode.
What image formats work?
PNG and JPG. PNG with a transparent background looks best; the Opacity slider applies on top of any transparency in the file.
Does Size mean the same thing for text and images?
Yes — it is the watermark's width as a percentage of the page width, so 50% spans half the page whichever type you use.
The tool says my PDF is encrypted — what now?
Password-protected PDFs must be opened with their password before they can be edited. Use the Unlock PDF tool first, then come back.
Is my PDF uploaded anywhere?
No. The document is parsed and rewritten by pdf-lib and rendered by PDF.js (the engine Firefox uses) entirely inside your browser. Nothing is transmitted or stored.