Merge PDF
Combine PDFs and reorder pages by dragging. Nothing is uploaded.
Watermark PDF
Stamp text or an image across pages with opacity control.
What it does. Watermarking a PDF overlays text or an image across its pages — CONFIDENTIAL, DRAFT, a company logo, or a recipient’s name. This tool applies the overlay with control over opacity, rotation, size, color and position, on every page or a selected range, entirely on your device.
Runs in your browserNothing uploadsNo signupWorks offline
How to use Watermark PDF
- Drop the PDF, then enter watermark text or upload a logo image.
- Set opacity, rotation, size, color and position, and watch the live preview update.
- Apply to all pages or a range, then download the watermarked PDF.
What settings make a watermark readable but not obstructive?
The goal is a mark that is unmistakable at a glance and still lets the document be read. Four settings decide that.
| Setting | Recommended | Why |
|---|---|---|
| Opacity | 15–25% | Below 10% is missed; above 35% obscures text |
| Rotation | 45° diagonal | Crosses lines of text so it cannot be cropped out |
| Size | 60–80% of page width | Covers the content area without spilling into margins |
| Color | Mid grey, or a desaturated brand color | Saturated red at 20% reads as pink and prints badly |
| Position | Center | Diagonal centered is the convention readers recognize |
A useful test: print the result in black and white. Many watermarks that look right on a backlit screen either vanish or turn into an unreadable smear on paper, and paper is where DRAFT and CONFIDENTIAL usually matter most.
Is a watermark actually security?
No, and it is important to be clear about this. A watermark is a deterrent and a provenance marker, not a protection mechanism.
Anything drawn onto a PDF page can be removed by someone with the right tools. The overlay is a separate object in the content stream, and editing software can delete it. Even a flattened watermark can be removed by rendering the pages, inpainting, and rebuilding.
What a watermark does well is establish intent and attribution. A document stamped DRAFT cannot be honestly presented as final. A document stamped with a recipient’s name discourages casual forwarding and identifies the source if it leaks — which is why per-recipient watermarking is standard practice for pre-release financial and legal material.
For actual protection, you need encryption with a user password, or a rights-management system. Neither is what a watermark is for.
Text or image watermark?
Text is the right choice for status marks — DRAFT, CONFIDENTIAL, SPECIMEN, INTERNAL USE ONLY, a date, a recipient name. It renders as vector text, stays sharp at any zoom, adds a few hundred bytes total, and remains legible when printed.
An image is the right choice for a logo or a signature. Use a PNG with a transparent background; a JPEG watermark brings an opaque rectangle with it, which will cover the text underneath regardless of the opacity setting.
For image watermarks, size matters for file weight: the image is embedded once and referenced on every page, so a 2 MB logo adds 2 MB to the document, not 2 MB per page.
Can I watermark only some pages?
Yes. The page range field accepts the same syntax as the split tool — 1-5, 12, 20- — and there are odd and even shortcuts.
The common case is skipping the cover page. A report with a designed cover usually looks better with the watermark starting at page 2, and applying it to 2- does exactly that.
Frequently asked questions
Can the watermark be removed?
By someone with PDF editing software, yes. A watermark is a deterrent and a provenance marker, not encryption. For real protection, use a password.
Will it appear behind or in front of the text?
You choose. In front at low opacity is the convention, because it reads as an overlay. Behind is subtler but can be hidden entirely by opaque page elements.
Can I use my logo?
Yes. Upload a PNG with transparency — a JPEG carries an opaque background that will block the content under it.
Does it work on scanned PDFs?
Yes. The watermark is drawn on top of the page content, whether that content is text or a scanned image.
Can I add different text to each page?
Not in one pass. Apply one watermark per range and repeat for each variation, or use the page-number token to insert a per-page value.
Does watermarking increase file size?
A text watermark adds a few hundred bytes total. An image watermark adds roughly the size of the image once, since it is embedded and referenced rather than duplicated per page.
Is my document uploaded?
No. The overlay is applied by pdf-lib in this page.
Guides for Watermark PDF
- Whiting Out and Drawing on a PDF7 min read
- Document Workflows, Trust and AI Tools8 min read
- What Is Hidden Inside a PDF7 min read
- How to Watermark a PDF Without Ruining It7 min read
- How to Sign a PDF Electronically That Counts8 min read
- PDF Security: What Works and What Does Not8 min read
- Adding Page Numbers, Headers and Bookmarks7 min read
- How to Add Stamps and Backgrounds to a PDF6 min read