Add a text watermark to a PDF

Diagonal draws one line along the page's diagonal through its centre; Horizontal draws one line through the centre; Tiled repeats the text in a grid over the whole page, at 45 degrees. Set the angle, from -90 to 90 degrees anticlockwise, to turn the line or the grid. Position puts one line, or an image, at the centre of the page or half an inch (12.7 mm) in from an edge or a corner, measured from the boxes its letters' ink fills, tops, tails and accents included: level or upright, the ink stands exactly that far in; at another angle a letter may leave a corner of its box empty, so the ink can stand a little further in. On a page too small for that, it is centred across that direction. A tiled watermark covers the whole page, so it has no position. Everything is placed on the visible page area and follows the page's rotation, so it reads correctly on rotated pages. The text's size is worked out per page from the page's size (its diagonal for Diagonal, its width for Horizontal, the length through the middle along a set angle, and its width per tile for Tiled), so mixed page sizes get proportionate stamps; a line too big for its page, by those boxes, is made smaller until all of it fits, down to 6 points; a line that would need less than 6 points on a chosen page is refused, the pages named, rather than cut off: shorten the text, or leave those pages out.

Not with this tool, and it is not a security feature: the stamp is ordinary semi-transparent text, or an image, drawn over the page content, and anyone with a PDF editor can delete it. Use it to label documents, not to protect them. Keep your original file if you may need an unmarked copy.

Latin, Chinese, Japanese and Korean text, up to 80 characters, such as CONFIDENTIAL or 机密, in the font you choose: Helvetica Bold, which viewers draw with their own copy of it, or Liberation Serif Bold or Liberation Mono Bold, loaded from this site the first time they are chosen (0.3 to 0.4 MB) and embedded as a small subset of the characters used. Characters those fonts cannot write are written with this site's own Noto Sans CJK when it has them (Simplified Chinese design; Traditional Chinese, Japanese and Korean characters and Cyrillic are in it too), embedded as a small subset of the characters used. With Helvetica Bold, a text that has any such character is written in Noto Sans CJK, its Latin letters, digits and spaces too, as before, except the few characters Helvetica Bold has and Noto Sans CJK lacks, which stay in Helvetica Bold: Š, š, Ž, ž, Ÿ, ˆ and ˜, and, when the common-Chinese part is all the text needs, also Œ, œ, ƒ, € and ™. Liberation Serif Bold and Liberation Mono Bold write every character they have themselves, letters such as Ć, Ł and Ő among them, except Hebrew, and leave only the others to Noto Sans CJK. Common Chinese (the 7,445 characters of GB2312, its 6,763 Chinese characters and 682 symbols such as ①, ℃ and →, with Chinese punctuation and full-width forms) needs only the font's common-Chinese part, 2.3 MB once; any other Chinese, Japanese or Korean character loads the whole font instead, about 22 MB once. Either is loaded from this site only when such text is first written, and your file and text stay on this device. Thai, Arabic, emoji and other scripts are in none of these fonts, and Hebrew, which the Liberation fonts have, would come out reversed, since a line is laid out left to right: the tool names the characters it cannot write and makes nothing. A character the chosen font and Noto Sans CJK both lack is named with any font here that has it: with Helvetica Bold, letters such as Ć, Ł and Ő, which Liberation Serif Bold and Liberation Mono Bold have.

Yes: choose An image, then a PNG or JPEG picture from your device; it is read in your browser and goes nowhere else. A PNG keeps its transparency, so a logo on a transparent background shows only the logo. Its width is a quarter, two fifths or three fifths of the page's width, in its own proportions, and smaller where the turned picture would otherwise run past the page. It is drawn at the opacity you choose, level unless you set an angle, and placed as a line of text is. One copy of the picture serves every page it is on, so the PDF grows by the picture once.

Yes. The preview is the first page you chose, stamped by the same code that makes the file and drawn by the same viewer (PDF.js), so the saved page looks the same: the watermark in the same place, font, size, angle, colour and opacity. Without a connection there is no preview, since that viewer is loaded from this site. A text in Helvetica Bold and an image are still added as set; Liberation Serif Bold, Liberation Mono Bold and the font for Chinese, Japanese or Korean are loaded from this site the first time the page uses them, and if that fails the tool says so and you can try again once you are back online.

No. The page loads a PDF engine into your browser and every operation runs on your device. You can check this yourself in the browser's network panel: after the page has loaded there are no upload requests. Closing the tab discards the file.

No. These basic tools are free and add no watermark of their own: this one adds only the watermark you choose, your own text or image. There are no page or file limits set by us; the practical limit is your device's memory.

Encrypted PDFs cannot be processed here. Remove the password first, then use this tool.

Nothing you open or type. While the tab is open, the tool pages keep a short list of the steps taken in it, in the tab's session storage: the step (page opened, started, succeeded, first success, used again or failed), the tool's name, the time, how many files were used and, for a failure, an error code; never a file name, the contents of a file or your text. It holds at most the latest 200 steps, and the browser deletes it when the tab closes. The page never sends it. Where a Report a problem button is shown, you can attach the last 20 steps to your report; nothing is attached unless you tick that box. In local storage the page keeps only choices you made: a Light or Dark theme until you choose System again, the language you picked with the EN / 中文 switch if it differs from your browser's language, and this tool in your recently used list if you switched that list on at the tools page.