Add Watermark to PDF — Text or Logo, Every Page

How to watermark a PDF in your browser

1. Choose the PDF to watermark.
2. Pick the watermark: your text ("CONFIDENTIAL", "DRAFT", "SAMPLE") or a logo image. Set opacity (15% is the standard ghost level) and size, and check Tile to repeat it diagonally across each page.
3. Hit Watermark & Download. Every page comes back carrying the mark, rendered under a neutral treatment that keeps the document readable.

When is a watermark the right tool?

Watermarks are for marking status, not hiding content: drafts in circulation, internal-only copies, samples sent to a prospect, a contract between parties where each copy is identifiable. The diagonal ghost is a convention everyone reads instantly, and "N of M"-style identification (adding a unique string per document) is a common extension — create the PDF once per recipient with their reference in the watermark and every leaked copy points back to its source.

Why text on the diagonal?

A horizontal watermark sits where lines of text sit, and competes with them for the eye. A 45° angle cuts across the reading flow instead of running along it, so at 10–20% opacity it is obvious when you look for it and quiet when you are reading. That balance is the whole design; the tool keeps it fixed so you cannot accidentally make an unreadable document.

Logo watermark or text watermark — which one?

Text for status (DRAFT, CONFIDENTIAL, SAMPLE). A logo for ownership and brand context, especially on public-facing samples. Logos work best as PNGs with transparency at a reasonable resolution (512px+ wide); a small JPEG logo will show its edges at 75% page size.

Does watermarking change the original?

Never. The download is a new file with the mark composited onto each page; your original stays exactly as it was on disk. That makes the workflow safe to repeat: watermark a copy for distribution, keep the clean master for yourself.

Is my document uploaded?

No. The mark is composited in your browser by the local PDF engine and the download is built from your own bytes. The network panel shows no outbound transfer of the file at any step.

FAQ

• Is my file uploaded to a server? No. The tool runs entirely in your browser — your file never leaves your device. You can verify it yourself: open the network panel and there is no upload request while you work.
• Do I need an account, and is it free? No account and no cost. It is free to use — no signup, no paywall, no daily limit.
• Which browsers does it work in? Any modern browser — Chrome, Edge, Firefox and Safari — on desktop or mobile.
• Is there a size limit? There is no server-side limit because nothing is uploaded. Practical limits come from your device's memory, which comfortably covers normal documents and photos.
• Does it work with encrypted PDFs? Standard PDFs work in every tool. If a file is password-protected, Unlock PDF opens it for you when you have the password, and Protect PDF applies a new 256-bit AES password. No tool bypasses encryption without the key.