Watermark PDF

Stamp text across every page of a PDF

A watermark tells anyone who opens a file how to treat it before they read a word. This tool lays one line of text — DRAFT, CONFIDENTIAL, a company name, a case number — diagonally across all pages in one pass, with control over color, opacity, font size, and angle.

When a text watermark is the right move

• Marking drafts for review. You send a contract or proposal out for comment but don't want a half-finished version mistaken for the signed copy. A faint DRAFT across each page makes the status obvious even after the file is printed or forwarded.
• Labeling confidential distributions. Board packs, salary letters, internal financials. A CONFIDENTIAL or INTERNAL USE ONLY stamp sets expectations and discourages casual resharing.
• Tagging copies by recipient. Stamping a name, client ID, or "Copy 3 of 8" on tender documents creates a light paper trail: if a leaked page turns up, the label tells you which copy it came from.
• Branding samples. Stamp your studio name or "SAMPLE — NOT FOR PRINT" across PDF previews before sending proofs.
• Marking superseded versions. Stamp VOID or SUPERSEDED on an old quote or policy so no one acts on it.

How the stamp actually works

The text is drawn directly into each page's content stream using PDFBox — it is not metadata or a separate annotation layer. Opacity is applied through a transparency graphics state, so at the default 15% the watermark sits behind your text without obscuring it; push it toward 60% for a bold, can't-miss stamp. The default 45-degree angle spans the page corner to corner, the convention most readers recognize as a watermark.

Because the words become part of the page, they survive printing, flattening, and re-saving — a viewer can't simply toggle them off. That permanence is the point, but it also means you should keep your original file if you ever need a clean copy.

Practical tips

• Start with the defaults (15% opacity, 60 pt, gray, 45°) and adjust only if the watermark fights with your content. Dark, dense pages read better with a lighter color and lower opacity.
• Keep the text short. A single word scales across the page cleanly; long sentences shrink to fit and lose impact.
• For a faint background tint, drop opacity to 5% and raise the font size. For a hard "do not use" warning, use red and 50%+ opacity. Set the angle to 0 for a flat, centered banner instead of a diagonal stamp.

Limitations and when to use a different tool

This tool stamps one line of text on every page — there's no image/logo watermark, no tiled pattern, and no way to mark only selected pages here. For those needs, reach for a related tool:

• [Sign PDF](/sign-pdf) places a PNG image (a signature, a logo, a stamp graphic) at a position you choose, rather than diagonal text across the whole page.
• [Edit PDF](/edit-pdf) adds text boxes, highlights, and redaction overlays to specific spots on specific pages — use it when placement matters more than a uniform mark.
• [Number pages](/number-pages) is the right tool for sequential "Page 1 of N" labels in a header or footer.
• A watermark is not access control. To stop someone opening or copying a file, use [Protect PDF](/protect-pdf) to add an AES password, and [Flatten PDF](/flatten-pdf) to lock form fields into the page.