How to add a watermark to a PDF
- Drop a PDF into the box above, or click it to choose one.
- Pick Text and type what the stamp should say — DRAFT, CONFIDENTIAL, a client's name, a date — or pick Image or logo and choose a picture.
- Choose one stamp per page or a tiled pattern, then set the size, angle and opacity.
- Look at the preview: it is the real finished page, rendered from the file you are about to download.
- Download the watermarked PDF. Every change rebuilds it, so there is nothing to click twice.
The file never leaves your device. That also means none of the limits that server-based watermark sites impose: no 200-page cap, no 50 MB cap, no “three tasks per hour”, no account.
Behind the text, not over it
A watermark has two jobs at once: it has to be seen, and it must not make the document harder to read. Most tools solve this by turning the opacity down until the stamp is faint — which dims the mark and still sits over every letter underneath it.
This tool writes the stamp underneath the page content by default. The words and images of your document are drawn on top of it, exactly as a printer would lay down a pre-printed sheet and then the text. The result is a mark that can stay strong enough to read while the paragraph over it stays perfectly sharp.
There is one case where you want the opposite. A scanned page is one big photo covering the whole sheet, so anything behind it is hidden completely — untick the option for scans and lower the opacity to 15–30% instead. The preview makes this obvious straight away: if the stamp disappears, the page is a scan.
Tiled or single
| Goal | Settings |
|---|---|
| Classic diagonal DRAFT across the page | Text, one stamp per page, 45°, 60% width |
| Hard to crop out of a screenshot | Tiled, 20–30% width, spacing 40% |
| Company logo in a corner | Image, one per page, position bottom right, 15% width, 0° |
| Recipient's name across a sent copy | Text with the name, tiled, low opacity, behind the content |
| Stamp only the cover | Pages 1 |
Size is given as a percentage of the page width, not in points, so the same setting looks right on A4, Letter, a landscape slide deck and a small scanned receipt. In a tiled layout, the spacing is measured against the stamp's own tilted size, which keeps the gaps even at any angle.
Logos and transparency
PDF files can carry PNG and JPG images directly, and a PNG's transparency is preserved, so a logo on a transparent background stays a logo rather than becoming a white rectangle. JPG has no transparency, so a JPG logo will show its background colour. Other formats — WebP, GIF, a screenshot from your phone — are converted to PNG first, keeping any transparency they had. The opacity setting then applies on top of that.
Rotated, cropped and mixed-size documents
A PDF page carries an instruction for how far to turn it when displayed, and a crop box that need not start at the origin. Tools that ignore these put the stamp sideways on a landscape scan or half outside a cropped page. Here the position, size and angle are all measured from the page as you see it, so a document mixing portrait text pages with landscape tables and a scanned insert gets the same stamp, the same way round, on all of them.
What a watermark can and cannot do
The stamp becomes part of the page content, so it is not a comment or an annotation that a reader can select and delete, and it survives printing, flattening and converting to images. That is enough to mark a document's status, discourage casual reuse, and make it obvious which copy went to whom.
It is not a security control, and any site that says otherwise is overselling. Someone with a full PDF editor can edit page content, including your stamp. If a document must not be changed or redistributed, that has to come from how you share it, not from a mark on the page. A tiled watermark at least makes cropping and screenshotting impractical, which is usually the real goal.
The rest of the document is left alone
Text stays selectable and searchable, images are not re-encoded, and links, bookmarks and form fields come through untouched — only the stamp is added. A text watermark costs a few kilobytes; an image watermark costs roughly the size of your image, embedded once and reused on every page.
Related tools: Add Page Numbers to PDF for numbering the same document, Sign PDF to add a signature rather than a stamp, Compress PDF if the watermarked file needs to be smaller, and Add Watermark to Image for photos rather than PDFs.