How to add a watermark to a PDF
- Choose your PDF. Click the box above and pick the file. It opens in this tab; nothing is sent anywhere.
- Type the text and style it. Use something like CONFIDENTIAL, DRAFT or COPY. Set the size, opacity, angle and colour.
- Add and download. Click Add watermark, then save the new PDF. Its name ends in
-watermarked.
Good to know
- Text only. The watermark is one line of up to 60 characters, centred on every page. Logo or image watermarks aren’t supported.
- Latin characters only. Letters A to Z, digits and common punctuation work. Other scripts and emoji show an error.
- The angles: diagonal either way, horizontal or vertical. Size runs from 20 to 140 points and opacity from 5% to 80%.
- The rest of the PDF is untouched. The watermark is drawn on top as text, so selectable text, links and images stay as they were.
- It’s a label, not a lock. Someone with a PDF editor could remove it. To stop people opening the file, add a password.
Your PDF stays on your device
Most online watermark tools upload your PDF to their servers. Here, the watermark is written into the file inside this browser tab, using the open-source pdf-lib library.
The page’s security policy tells your browser to block uploads, so the document can’t leave your device even by accident. You can check: open your browser’s developer tools, watch the Network tab, and watermark a file. How InTheTab works
You’ll also see a few small requests to Google Analytics. That’s our visit counter, and it never receives your files. Privacy policy
Questions
Is it safe to watermark a confidential PDF here?
Yes. The file is read and changed by your own browser and is never uploaded. We never get your files or text: the site has no accounts, and its only analytics, Google Analytics, counts visits without ever seeing what you add here.
Can I watermark only some pages?
No, the same watermark goes on every page. To mark only part of a document, split it, watermark the part you need, then merge the files again.
Will the watermark cover my text?
It sits on top of the page, but at the default 18% opacity the text underneath stays easy to read. Lower the opacity if it gets in the way.
Do I need to install anything or sign up?
No. It runs in any modern browser on Windows, Mac, Linux, Android or iPhone. It’s free and there’s no sign-up. The only watermark added is yours.