💧 Add Watermark to PDF
Quick answer
This tool stamps your text diagonally across the centre of every PDF page, at the size and opacity you set. It is free, and the watermarking runs in your browser — your file is never uploaded to a server.
Drop a PDF file here
Drag & drop a file here, or
🔒 Your files are processed on your device — nothing is uploaded.
✅ 100% free · 🔒 Runs in your browser — files never leave your device · 🚫 No sign-up
How to use the Add Watermark to PDF
- Drop your PDF into the box above or click Choose file to select it.
- Type your watermark text, such as CONFIDENTIAL or DRAFT.
- Set the font size and drag the opacity slider until it looks right.
- Click Add Watermark & Download to get the stamped PDF.
Frequently asked questions
Can the watermark be removed later?
The text is drawn onto each page as part of the PDF content. Keep a copy of your original file if you may need an unstamped version.
Which characters can I use in the watermark?
Letters, numbers and common punctuation work best, because the built-in Helvetica font supports standard Latin characters.
What opacity should I choose?
Around 0.25–0.4 is typical: clearly visible across the page without hiding the document text underneath.