Add Watermark to PDF

How to add a watermark to a PDF

1. Drop a PDF file on the drop zone, or click it to choose one. A Preview of the first page to be marked appears and follows every change.
2. Under Watermark, choose Text or Image. For text, type it (the default is “CONFIDENTIAL”), then pick a Font, a Font size (pt) and a Color. For an image, click Choose an image… and set its Width (% of the page width).
3. Set the Opacity and the Angle (°). 45° runs diagonally from the bottom left to the top right; 0° is level.
4. Under Layout, choose Once with a Position and a Distance from the edge (mm), or Tiled (repeated across the page) with a Spacing between copies (mm).
5. Optionally tick Place behind the page content.
6. Under Pages, keep All pages or choose Selected pages and type them, for example 1, 3-5.
7. Click Add watermark, then Download. The file is named after the original, for example contract_watermarked.pdf.

Text or image?

A text watermark is the classic “DRAFT”, “CONFIDENTIAL” or “COPY”. It’s written with one of the standard PDF fonts (Helvetica, Times or Courier, regular or bold), which every PDF reader has built in, so the file hardly grows. The text stays real text: it’s sharp at any zoom and prints cleanly.

Standard fonts only cover Western European characters: accented letters, €, curly quotes and dashes work, but Cyrillic, Greek, Chinese, Arabic or emoji don’t, and the tool says which characters it can’t write. Embedding a font to support other scripts is out of scope here. The workaround is an image watermark: make a PNG of your text in any program and use it as the watermark.

An image watermark is typically a logo or a stamp. A PNG with a transparent background gives the best result; JPEG, WebP and GIF are accepted too (WebP and GIF are converted to PNG). The image keeps its proportions, and its size is a percentage of each page’s width, so it scales with the page.

Opacity, angle and layout

Opacity from 20 to 40% keeps the page readable while making the mark obvious. The angle turns the watermark around its centre, counter-clockwise; use a negative angle to go the other way.

Once places a single copy at one of nine positions. The whole turned watermark stays inside the page, at the chosen distance from the edges. Tiled repeats it across the page in staggered rows, which makes it much harder to crop out of a screenshot or a scan.

Rotated pages, and “behind the content”

Positions and angles apply to the page as you see it. If a page is stored sideways and displayed in landscape, or has been cropped, the tool works out the visible area and orientation, so a 45° watermark looks the same on every page.

By default the watermark is drawn on top of the page. Place behind the page content draws it underneath, so text and images stay crisp over it. That only shows on pages with a transparent background: a scanned page is one opaque picture and will hide it.

A watermark is added content, not protection. Anyone with a PDF editor can remove it. For stronger deterrence, use the tiled layout and flatten or print the file to PDF afterwards.