How to use the watermark pdf
- Drop a PDF onto the drop zone or click to choose one.
- Type your watermark text and choose the font, size, angle, colour, opacity and placement (centred or tiled).
- Optionally turn on an image watermark and choose a PNG or JPEG logo, its opacity and width.
- Limit it to certain pages if needed, check the live preview, then click Add watermark and download.
Worked example
"CONFIDENTIAL" across every page
With Helvetica Bold at 60 pt, 25% opacity, 45 degrees and centred placement, the word is drawn once in the middle of each page, rotated so it reads diagonally from bottom left to top right. Choosing tiled repeats it in a staggered grid that covers the page.
How it works
Text is drawn with pdf-lib using one of the 14 standard PDF fonts, centred on the page's visible area and rotated around its centre. Pages that are themselves rotated get the page rotation added so the angle looks the same to the reader. Images are embedded once and drawn with the opacity and width you choose.
Assumptions
- Standard PDF fonts use WinAnsi encoding, so only Latin characters and common symbols are allowed. Other characters are rejected before processing.
Frequently asked questions
Are my files uploaded?
No. Your PDF is processed in your browser on your own device and is never sent to our server. You can disconnect from the internet after the page loads and the tool still works.
Why can I not use emoji or non-Latin text?
The watermark uses the standard fonts built into every PDF reader, which only cover Western European characters. Using them keeps files small and needs no font download. For other scripts, use an image watermark made from your text.
Can a watermark be removed?
The watermark is drawn on top of the page content. Someone with a PDF editor can remove it, so treat it as a clear label and deterrent rather than protection.
Can I use a password protected PDF?
Not for editing. Encrypted or permission-restricted PDFs are refused, because editing them without decrypting would create a broken file or bypass restrictions set by the author. If you are allowed to, remove the protection in the software that created it first.
Limitations
- Files up to 100 MB are accepted, but very large or complex PDFs depend on your device memory and can be slow on phones.
- Text watermarks support WinAnsi (Western European) characters only.
- The watermark is a separate layer on top of the page and can be removed with editing software.
- Encrypted or permission-restricted PDFs cannot be watermarked.