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How to Add a Watermark to a PDF (Text or Logo, Free)

4 min readUpdated 5 October 2026

To add a watermark to a PDF, open Stamp PDF and drop in your file. The Watermark is already on: type your own text, or switch to Image to use a logo, adjust Opacity and Rotation, then press Stamp PDF to download the watermarked copy.

It's free with no account, works on a computer or a phone, and adds no branding of its own. The watermark is applied inside your browser and the file is never uploaded — sensible for the confidential documents that usually need one.

Do it now with Stamp PDFFree, no sign-up, works on any device.

Step by step

  1. 1Open Stamp PDF and add your fileGo to the Stamp PDF tool and drop your PDF onto the page, or click to choose it. A preview shows the watermark on your first page straight away.
  2. 2Choose text or a logoKeep Text and replace “CONFIDENTIAL” with your own words — such as DRAFT, COPY or your company name — or choose Image and tap Choose a logo or image. A PNG with a transparent background works best.
  3. 3Set the lookFor text, set the Size (10–160 pt) and Colour; for an image, set its Width as a percentage of the page. For both, adjust Opacity (5–100%) and Rotation (−90° to 90°).
  4. 4Place it on the pagePick one of the nine spots in the Position grid — the center is the classic choice — or switch on Tiled to repeat the watermark across the whole page.
  5. 5Choose pages and stampUnder Pages, keep All pages or choose Custom and type pages such as 1-3. Press Stamp PDF (or Ctrl/⌘ + Enter). The copy is saved with “-stamped” added to its name; your original file is untouched.

Settings that look professional

The watermark is drawn on top of the page, so the right settings keep your document readable:

  • Status stamps (CONFIDENTIAL, DRAFT): center, 45° rotation, opacity around 15–30%. The default red at 25% is a good starting point.
  • Logo in a corner: an image at 10–20% width, Position bottom right or top right, opacity 60–100%.
  • Copies of ID cards and documents: write what the copy is for, such as “For account opening only”, and switch on Tiled so it covers the whole page and is hard to crop out.

Tip: Use the page arrows above the preview to check a few pages — a watermark that suits a text page can hide a chart or photo on another.

Text or image watermark?

Text is quickest for status labels and works in any language. Thai and other non-Latin text is embedded as a sharp image, so a watermark like “สำเนา” prints cleanly.

An image suits a logo or stamp. JPG has no transparency, so a JPG logo shows as a box with its background; a PNG with a transparent background blends in. WebP and SVG images are accepted and converted automatically.

Common problems and fixes

Text underneath is hard to read — lower the Opacity, or reduce the size and move the watermark off the main content.

Your logo has a white box around it — make a transparent version with Background Remover, then choose that PNG as the image.

Only some pages need it — choose Custom under Pages; the line under the box shows how many pages are selected. Add a second watermark to other pages by stamping the result again.

The PDF won't open — it's usually password-protected or damaged. Open it with its password, save a new copy (“Print › Save as PDF”) and watermark that.

Does a watermark stop people copying?

A watermark is part of the page content, so it shows on screen and in print and travels with the file. It discourages casual reuse and makes clear where a copy came from.

It isn't a lock, though: someone with editing software can still work around it. A tiled watermark across the content is much harder to remove than a small one in a corner. For sending, Compress PDF shrinks the result, and Sign PDF adds your signature.

Questions people ask

How do I add a watermark to every page of a PDF?
Leave Pages on All pages, which is the default. The same watermark is placed in the same spot on every page when you press Stamp PDF.
Can I use my logo as a watermark?
Yes. Choose Image, pick your logo file and set its width, opacity and position. A PNG with a transparent background gives the cleanest result.
Can I add a Thai watermark?
Yes. Type Thai text as usual. It's embedded as a sharp image because the standard PDF fonts can't display Thai, and it prints correctly.
Can I add page numbers at the same time?
Yes. Switch on Page numbers or Header & footer alongside the watermark and everything is stamped in one go.
Is it safe to watermark a PDF online?
With this tool, yes: the watermark is added in your browser and the file is never uploaded to a server.
Do it now with Stamp PDFFree, no sign-up, works on any device.

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