PDF Watermark

Add a text watermark to PDF pages in your browser. Choose opacity, position, and page range—free, no upload, local pdf-lib processing.

Is my PDF uploaded to a server?

No. Watermarking runs entirely in your browser with pdf-lib. The file never leaves your device. Browser memory limits still apply on very large scanned PDFs, so keep a backup before batch stamping.

Can I use Chinese or emoji in the watermark?

The built-in font is Helvetica and works best with Latin letters, numbers, and basic punctuation. Complex scripts may fail to embed—use a short Latin phrase for reliable stamps. If you must stamp Chinese, convert the phrase to a short Latin project code for reliable embedding.

How opaque should the watermark be?

Start around 0.3–0.4 opacity for readable body text. Increase for stronger deterrence on screenshots; decrease for print-heavy documents. Print a single test page before batching hundreds of pages so opacity looks correct on paper.

Can I watermark only some pages?

Yes. Enter a page range like 2-4, 7 or leave empty to stamp every page. Page numbers start at 1. Ranges are inclusive and use commas for lists, matching other Power Tools PDF utilities.

What is the maximum file size?

PDFs up to 25 MB are supported, matching other Power Tools PDF utilities. Extremely large files near the limit may take longer because the entire PDF is rewritten locally.

Will watermarking break digital signatures?

Editing pages can invalidate signatures. Keep a signed original and watermark only copies intended for review. When in doubt, watermark a copy and keep the signed original in cold storage.

Do password-protected PDFs work?

Encrypted PDFs that require a password to open are not supported. Unlock with authorized software first, then watermark locally. Remove encryption offline with tools you trust, then return here for stamping.

Does watermarking reduce PDF quality?

Text watermarks are drawn as vector-like PDF text overlays and do not re-rasterize the whole page, so quality loss is minimal. Vector text and images under the watermark remain at their original resolution.

Need PDF to images, images to PDF, or text extract?

Use sibling tools on this site: PDF to Images (PDF to PNG/JPG), Images to PDF (JPG/PNG to PDF), and PDF Text Extractor for plain-text convert-PDF-doc style extracts. Pair with Merge, Split, or Compress PDF for a full browser-local toolkit—no uploads.

Is this PDF watermark tool free?

Yes. Free, no login, and no upload to a server. Unlimited personal use fits the Power Tools free traffic-tool model with ads only outside the workspace.

Which watermark position should I choose?

Diagonal is the classic confidential stamp. Center is more aggressive. Top or bottom keeps the middle of the page clearer for reading. Diagonal watermarks rotate with the page coordinate system so landscape sheets still read correctly.