About watermarking a PDF
This tool adds a text watermark to every page of a PDF. Set the text, font size, colour, opacity and angle, and it stamps a diagonal watermark across each page, ready to download. It is ideal for marking documents as Confidential, Draft or with your brand. It runs in your browser, so nothing is uploaded.
How PDF Watermark works
How to watermark a PDF
- Drop your PDF onto the box.
- Type the watermark text and set the size, colour, opacity and angle.
- Click to apply it to every page and download.
Get the look right
A semi-transparent, angled watermark (around 20% opacity at 45°) stays readable without hiding the content. Use red for "Confidential" or a light grey for a subtle brand stamp.
Private and free
The watermark is applied locally with the PDF-lib engine — your document never leaves your device, with no sign-up and no limits.
Common uses
- Mark a PDF as Confidential or Draft
- Brand documents with your name
- Protect documents before sharing
- Label proofs and review copies
- Add a Sample or Specimen stamp
- Discourage unauthorised copying
- Mark internal documents
- Stamp every page at once
Frequently asked questions
How do I add a watermark to a PDF?
Drop the file, type your text, adjust the style, and download — it is applied to every page.
Can I change the colour and opacity?
Yes — set the colour, opacity and angle to taste.
Does it watermark every page?
Yes — the watermark is stamped across all pages.
Will the document stay readable?
Yes — a semi-transparent watermark sits over the content without hiding it.
Are my files uploaded?
No — watermarking happens entirely in your browser.
Can I use it to mark documents Confidential?
Yes — type CONFIDENTIAL (or any text) and choose a colour.
Does it support angled text?
Yes — set any angle, with 45° as a common diagonal.
Is it free?
Yes — completely free with no sign-up.