Add a Watermark to a PDF

When to use Add Watermark to PDF

Use this to mark drafts as "Confidential" or "Draft," brand a document with a logo watermark, or discourage unauthorized redistribution of a shared copy. It marks the visible page only — it is not a copy-protection or DRM mechanism.

How to Add a Watermark to a PDF

1. Select a PDF.
2. Add a text or image watermark.
3. Adjust position, rotation, size, and opacity.
4. Choose the pages to apply it to, then preview and export.

What this tool changes

• Stamps a repeating or single watermark on the selected pages.

What it preserves

• Existing page content — the watermark is layered in front of or behind it.

Good to know

• Extremely dense existing page content can make a low-opacity watermark harder to see, and vice versa.

A watermark is page content, not a layer

The watermark is drawn onto each page like any other text or graphic. After export there is nothing marking it as special — it is not a separate layer that can be toggled off, and no password governs it.

That is what makes it durable: it survives printing, it survives being forwarded, and it cannot be dragged away by accident. It is also why removing one later means editing page content, which is a genuinely hard operation rather than an undo.

So keep the unmarked original. If you need a clean copy later, going back to the file before the watermark is the only straightforward route — which is why this writes a new file and never modifies your source.

Opacity, size, and placement

A watermark has to be readable enough to serve its purpose and faint enough to leave the document usable. Too solid and it competes with the text; too faint and it disappears when printed, which is exactly when it usually matters.

Diagonal across the page is the convention for status marks like DRAFT or CONFIDENTIAL, because it crosses the text without settling on any one line. A smaller mark in a corner suits attribution or a document reference, where the point is identification rather than warning.

If the document will be printed, check a printed page rather than a screen. Printers render light greys very differently from displays, and a watermark that reads perfectly on screen can vanish or turn into a solid block on paper.

It marks a document, it does not protect one

A watermark deters casual misuse and makes the status of a copy obvious at a glance. It does not prevent anything. It does not stop copying, forwarding, printing, or extracting the text underneath it.

If the requirement is that only certain people can open a document, that is encryption — Protect PDF sets a real password. If the requirement is proving a document is unaltered or who approved it, that is a signature. Watermarking is a labelling tool, and treating it as a security control is a common and expensive mistake.

Used honestly, it is very good at what it does: a page marked DRAFT is far less likely to be quoted as final, and a page marked with the recipient's name is far less likely to be forwarded casually.

What a watermark weighs, and why tiling costs ten times more

A single diagonal watermark across all three pages of a four-megabyte scan added 1,274 bytes in our measurement. Switching the same watermark to tiled — repeated across each page rather than placed once — added 12,875 bytes, ten times as much.

The difference is simply repetition: a tiled watermark draws the text many times per page, and each repetition is another instruction in the page’s content stream. On a four-megabyte scan neither number matters. On a small text-only document, a tiled watermark can be a visible fraction of the file, which is worth knowing if you are watermarking in bulk.

Both numbers stay low because the font is not embedded. The output names Helvetica-Bold and carries no font program, so the mark renders using whatever the reader’s viewer supplies. That is the right trade for a watermark, where the shape of the letters matters far less than the fact that they are there.

Watermarking also leaves the document’s own details alone: title, author, subject, and creator all survive, because the mark is drawn onto the existing pages rather than into a rebuilt file.

Placement follows the page as you see it. A mark set to the top-right corner lands in the top-right of the preview whether the file arrived turned or you turned it here, and a diagonal mark keeps its angle relative to the page rather than to the sheet underneath it. That was not always true: on a page turned a quarter turn clockwise, a top-right mark used to be drawn in the bottom-right, and each of the other two turns put it somewhere different again. Every quarter turn is now pinned by tests that check where the mark lands on screen, not where it sits in the file.