Add a semi-transparent text watermark, diagonal or horizontal, to the centre of every page of a PDF, with your choice of text, size, colour and opacity.
How to watermark a PDF
- Choose the PDF.
- Type the watermark text and adjust size, opacity, angle and colour.
- Press Add watermark to download.
Good watermark settings
For a readable document that is clearly marked, use 20–30% opacity, a font size of 50–80 and a diagonal angle. Red or grey are the usual colours.
Frequently asked questions
Can I use non-English text?
The built-in PDF fonts support Western European characters. Urdu, Arabic and other scripts are not supported in this tool yet.
Are my PDF files safe?
Yes. The PDF is read and written by JavaScript libraries (pdf-lib and Mozilla pdf.js) inside your browser. The file is never uploaded, so confidential contracts, bank statements and ID scans stay on your device.
Updated October 2026 · Built and tested by Sharjeel Tahir · How our tools are tested