Add a watermark to a PDF
Stamp CONFIDENTIAL, DRAFT or your own logo across a PDF, with a live preview and without uploading the file anywhere. Watermarking is part of a ThekkelSoft Pro membership.
How to watermark a PDF without uploading it
- Open your PDF — drag and drop it or browse from your device. It is opened directly in your browser, not uploaded.
- Design the mark — type your text (or pick a logo), then set the layout, angle, size, colour and opacity. The page preview shows exactly what you will get.
- Choose where it sits — blended on top, plainly on top, or behind the page content. Restrict it to a page range if you only need it on some pages.
- Download — the watermark is drawn into the page content and a new PDF is saved. Your original file is never modified.
Choosing a layout: diagonal, tiled or horizontal
Diagonal is the classic single mark across the middle of the page at −45°, which reads clearly without hiding much of the document. Use it for CONFIDENTIAL, DRAFT or COPY on contracts and reports.
Tiled repeats the mark in a staggered grid over the whole page. It is much harder to crop out, which makes it the right choice for samples, previews and documents you are sharing but do not want reused. Turn the opacity down and the spacing up so the page stays readable.
Horizontal places one upright mark in the centre — the least intrusive option, and the natural one for a logo.
Adding a transparent watermark
A watermark has to be read and seen through at the same time, and opacity is the control that decides which of the two it does. Around 10–20% is enough for a light tint that never competes with the text; 30–50% is the usual range for a DRAFT or CONFIDENTIAL mark that has to be unmissable on a printout; anything higher starts to cost you the document underneath.
Opacity is not the only lever. Blend multiplies the mark into the page instead of laying it over the top, so the words beneath stay legible even at a heavier setting, and Behind text puts it under the content altogether — the cleanest look on a text document, though invisible on a scan, which is a single opaque image covering the page. A logo with its own transparency keeps it: drop in a PNG or SVG with an alpha channel and the transparent areas stay transparent, with the opacity slider applied on top of that.
Whatever you choose, the live preview shows the real result page by page, so the setting is a decision you make by looking rather than by guessing.
Private by design
Most online watermark tools upload your document to their servers, which is exactly the wrong trade for a file you have just labelled “confidential”. Ours doesn’t — the watermark is applied inside your browser, so contracts, statements and ID scans never leave your machine, enforced by a Content-Security-Policy that blocks the page from talking to any third-party server. Read more in our privacy policy.
Working on the same document? Add page numbers, annotate it in the full PDF Editor, or shrink the result with the PDF Compressor.
Frequently asked questions
Why do I need a membership for this tool?
Because it writes a new version of your document, and every tool that alters a document's contents is offered only to signed-in members who have accepted our Acceptable Use Policy — the undertaking to use them only on files you own or are authorised to modify. Watermarking is part of a ThekkelSoft Pro membership. Nothing about your file changes: it is still stamped and saved entirely in your browser and never uploaded. Merging, splitting and compressing PDFs remain free and need no account.
Do you add a watermark of your own, or limit pages?
No to both. Your file gets exactly the mark you configured and nothing else, on as many pages as you like — the job runs on your own device, so there is no per-page cost to pass on.
Can I watermark a PDF without uploading it?
Yes. The file is opened, watermarked and saved entirely inside your browser and is never transmitted. A Content-Security-Policy makes the browser block requests to other origins, so this is enforced technically rather than just promised.
How do I make the watermark transparent?
Use the opacity slider — roughly 10–20% for a light tint that stays out of the way, 30–50% for a DRAFT or CONFIDENTIAL mark that has to read clearly on a printout. "Blend" also helps: it multiplies the mark into the page so the text beneath stays legible even at a heavier setting. A logo with its own transparency keeps it, because a PNG or SVG alpha channel is preserved and the opacity setting applies on top of it.
Can I use my company logo instead of text?
Yes. Switch to the "Image / logo" tab and pick a PNG, JPG or SVG. It is scaled as a percentage of the page width, and the opacity, angle and tiling controls work exactly the same as for text.
What is the difference between blend, on top and behind?
"Blend" draws the mark on top but multiplied, so the text underneath stays readable — the best default. "On top" is a plain overlay at the opacity you choose. "Behind text" puts the mark under the page content, which looks the most professional on text documents but is completely hidden on scanned pages, because a scan is one opaque image covering the whole page.
Can I watermark only some pages?
Yes. Leave the Pages box empty to stamp every page, or type ranges like 1-3, 5, 8-10 to restrict it. The preview updates as you move between pages so you can check before downloading.
Can the watermark be removed later?
The watermark is drawn into the page content, so it is not a layer that can be toggled off, and it survives normal viewing, printing and re-saving. It is not a security feature though — anyone determined enough can edit any PDF. For access control, use a password instead.
Will it work on a scanned PDF?
Yes, as long as you use "Blend" or "On top". A scan is a full-page image, so a watermark placed behind it would never be visible.
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