Add a watermark to a PDF

Why add a watermark to a PDF

A watermark tells everyone who opens a document what it is before they read a word: DRAFT on a contract that is still being negotiated, CONFIDENTIAL on a salary overview, COPY on a certificate you send to a landlord, or your company logo on a price list you hand out. This tool writes the watermark into the PDF itself, so it shows in every reader and on paper. Type a text or pick a PNG or JPG image, then choose where it goes: diagonally across the middle, centred, at the top or bottom, or repeated over the whole page so it cannot be cut out with a simple crop. Set the size and the opacity so the page underneath stays readable, pick a colour for text, and limit it to certain pages if you like. Pages that are stored rotated or in landscape get the watermark the right way up, the same as all the others.

How to watermark a PDF

1. Drop your PDF in the box, or click to choose it.
2. Type the watermark text, or switch to Image and choose a PNG or JPG. Pick position, size, opacity and, for text, the colour.
3. Click Add watermark and download the PDF.

What changes when you convert

A watermark is a deterrent, not a lock

The watermark is added as a layer on top of each page. It makes a copy obviously marked and is hard to remove from a printout or a screenshot, but someone with a PDF editor can select and delete it in the file. If people must not change or copy the content, a watermark alone does not stop them.

Opacity and readability

At 20 to 30 % a grey text is clearly visible while the page underneath stays easy to read, which is why 30 % is preselected. Solid colours at 100 % cover what lies below them, which suits a small logo in a corner of the page better than a large text across it.

Letters outside the built-in font

Text is written with Helvetica Bold, which covers English and Western European letters and stays sharp at any zoom. A text with other characters, such as Cyrillic, Greek or Chinese, is drawn as a picture of the text instead. It looks the same, but it cannot be selected or found by a search.

Images keep their transparency

A PNG logo with a transparent background is placed with its transparency, so only the logo shows. A JPG has no transparency and always brings its rectangular background along; at low opacity that shows as a light box. The image keeps its proportions and is never stretched.

Signed and protected PDFs

Adding a watermark changes the document, so a digital signature is no longer valid afterwards. Encrypted PDFs, even ones that open without a password but restrict editing, cannot be changed here; the tool says so instead of producing a broken file.