PDF Watermark

A free, private PDF watermark tool that stamps a text or image mark onto every page of a PDF — or just the pages you choose. Add a bold diagonal CONFIDENTIAL banner, a faint DRAFT label, a COPY notice, or your own logo, with full control over opacity, position, rotation and tiling. It is built for anyone who needs to mark documents before sharing them: agencies sending proofs, legal and finance teams labelling sensitive files, photographers protecting portfolios, or anyone who simply wants a SAMPLE stamp on a handout. Everything happens inside your browser — your PDF is read into memory, watermarked locally with the pdf-lib engine and downloaded directly. Nothing is uploaded, so it works on confidential material and even offline once the page has loaded.

How it works

When you choose a PDF, the tool parses it locally and reads the real size of every page. For a text watermark it embeds one of six standard fonts (Helvetica, Times and Courier, regular and bold), measures the text at your chosen size, and draws it at the position you pick with the colour, opacity and rotation you set. For an image watermark it embeds your PNG or JPG and scales it to a percentage of the page width, preserving the aspect ratio and any PNG transparency. You can place the mark at any of nine anchor points — corners, edge centres or dead centre — or switch on tiling to repeat it across the whole page with adjustable spacing, which is the classic way to make a document hard to lift content from. A page-range box (for example 1-3,5) lets you limit stamping to specific pages, and a per-page margin keeps the mark off the very edge. A schematic live preview redraws on every change so you can dial in the look before committing. Your settings are saved in this browser via localStorage, so the next document you open starts from where you left off.

Example

You need to send a draft contract to a client but want it clearly marked. Upload the PDF, click the CONFIDENTIAL preset (which sets red text at 45 degrees), drop the opacity to about 25% so the clauses stay readable, and leave the page box blank to cover all pages. Click Apply watermark and a file named contract-watermarked.pdf downloads with a diagonal red stamp on every page.

For a logo instead, switch to Image mode, upload a transparent PNG of your brand mark, set its width to 35% of the page, turn on tiling, and you get a repeating, semi-transparent brand pattern across each page — useful for proofs and portfolio PDFs.

Every page is processed on your device — no figures, no files and no logos ever leave your browser.