Watermark PDF

Protect your documents by adding custom text watermarks. Control font, size, color, opacity, rotation, and position. Apply to all pages or specific page ranges.

100% Private — files never leave your browser

Your files never leave your browserVerify →

Select Files

Configure

Download

0/3 free today

Drop a PDF file here

or click to browse from your device

Select Files

Your files stay on your device — 100% private

PDF, APPLICATION/PDF

How it works

Upload your file

Drag & drop or click to select. Files stay on your device — nothing is uploaded.

Adjust settings

Configure options and preview before processing.

Download result

Get your file instantly. No signup, no email required.

Frequently Asked Questions

Our free PDF watermark tool lets you customize the text content, font, size, color, opacity, and rotation angle. Position the watermark anywhere on the page and apply it to all pages or a specific range.

Currently, One23PDF supports text-based watermarks with full customization. Image watermark support is planned for a future update. Text watermarks are ideal for adding 'CONFIDENTIAL', 'DRAFT', or company names to your documents.

You have full control over the watermark opacity, so you can make it subtle enough to be visible without obscuring the document content. We recommend using 20-40% opacity for a professional look that maintains readability.

Watermarks added by One23PDF become part of the PDF content. If you need to make changes, simply re-process your original PDF with updated watermark settings. Always keep your original unwatermarked file as a backup.

Related Tools

Add Page Numbers

Add customizable page numbers with flexible positioning

Edit PDF

Add text annotations and labels to PDF pages

Sign PDF

Add electronic signatures to PDF documents

Add Header & Footer

Add headers and footers to PDF documents

Need more PDF tools?

Explore our full suite of 30+ free PDF tools — all running securely in your browser.

Browse All Tools

Why Watermark PDFs?

Watermarking is the practice of overlaying text or images onto document pages to indicate ownership, status, or confidentiality. Common watermarks include "CONFIDENTIAL," "DRAFT," "SAMPLE," and company logos. They serve as a visible deterrent against unauthorized use and help readers understand the document's intended purpose at a glance.

One23PDF's Watermark PDF tool lets you add fully customizable text watermarks to any PDF document. Control the text content, font size, color, opacity, rotation angle, and position on the page. Apply the watermark to every page or target specific page ranges — all without uploading your document to any server.

Watermarking is essential for professionals who share documents externally. A "DRAFT" watermark prevents recipients from mistaking a work-in-progress for a final version. A "CONFIDENTIAL" stamp reminds readers of their obligations. And a branded watermark with your company name reinforces your identity on every page.

Benefits of Watermarking PDFs

Protect Your Intellectual Property

A visible watermark discourages unauthorized copying and distribution. Even if someone screenshots or prints your document, the watermark remains, tying the content back to you.

Brand Your Documents

Add your company name, logo text, or website URL as a subtle background watermark. Every page becomes a branding opportunity that reinforces your professional identity.

Mark Document Status

Clearly label documents as DRAFT, FINAL, APPROVED, or VOID. This prevents version confusion and ensures reviewers know exactly which iteration they are reading.

Deter Unauthorized Sharing

Personalized watermarks (e.g., a recipient's name or email) make it easy to trace leaks. If a confidential document surfaces publicly, the watermark identifies who shared it.

How to Watermark a PDF with One23PDF

1
Upload your PDF
Drag and drop your PDF file onto the upload area. The document is loaded locally in your browser — your file is never sent to any external server.
2
Enter your watermark text
Type the text you want to overlay on each page. Common examples include "CONFIDENTIAL," "DRAFT," "DO NOT COPY," or your company name.
3
Customize appearance
Adjust the font size, color, opacity, and rotation angle. Choose whether the watermark appears in the center, header, or footer area. Preview the result in real time.
4
Select target pages
Apply the watermark to all pages, odd pages only, even pages only, or a custom page range. This flexibility lets you watermark cover pages differently from body pages.
5
Download the watermarked PDF
Click Download to save the watermarked file. The original PDF remains unchanged on your device, and the new file includes your watermark on every selected page.

Common Use Cases for PDF Watermarking

Adding "CONFIDENTIAL" to legal contracts, NDAs, and sensitive agreements before external review
Stamping "DRAFT" on proposals, reports, and presentations during internal review cycles
Branding photography proofs, design mockups, and creative assets with your studio name
Marking academic papers as "SAMPLE" or "REVIEW COPY" to prevent unauthorized distribution
Adding "DO NOT COPY" to proprietary training materials and company handbooks
Personalizing documents with recipient names to trace the source of any leaks
Overlaying "VOID" on canceled invoices, contracts, or certificates to prevent reuse

How Client-Side PDF Watermarking Works

One23PDF uses the pdf-lib library to overlay text on each PDF page. The watermark is drawn as a text element with configurable opacity, placed at the specified coordinates on the page's content stream. The process preserves all existing content — text, images, form fields, and annotations — while adding the watermark layer on top.

Opacity control is key to effective watermarking. One23PDF renders the text with an alpha channel value you specify, typically between 10% and 40%. This ensures the watermark is visible enough to serve its purpose without obscuring the underlying content. The rotation angle lets you tilt the text diagonally — the classic watermark look — or keep it horizontal for headers and footers.

Because everything runs in JavaScript within your browser, the watermarking process is nearly instantaneous. A 100-page PDF can be watermarked in under two seconds. There is no server queue, no processing delay, and no risk of your document being cached on a remote system.

Watermarking as Part of a Workflow

Watermarking often comes at the end of a document preparation workflow. You might first <a href="/merge-pdf">merge several PDFs</a> into a single document, then <a href="/add-page-numbers">add page numbers</a> for easy reference, and finally apply a watermark to mark the document's status. One23PDF makes this chain of operations seamless because every tool runs locally in your browser — no uploads between steps, no waiting for server processing.

For documents that need both a watermark and a signature, use the <a href="/sign-pdf">Sign PDF</a> tool after watermarking. The signature is added as a separate annotation layer, so it sits on top of both the watermark and the original content.

One23PDF vs. Other Watermarking Tools

Adobe Acrobat Pro offers robust watermarking but requires a $19.99/month subscription and desktop installation. Online tools like ILovePDF and Sejda provide free tiers but upload your documents to cloud servers, impose daily limits, and may add their own branding to free-tier output.

One23PDF is free to use with generous daily limits, no watermarks of its own, and no server uploads. Your documents stay on your device throughout the entire process. For businesses handling confidential materials — law firms, healthcare providers, financial advisors — this privacy guarantee is not just a convenience but a compliance requirement.

The customization options in One23PDF rival paid tools: full control over text, font size, color, opacity, rotation, and page targeting. Whether you need a subtle background brand or a bold "CONFIDENTIAL" stamp, One23PDF gives you the flexibility to create exactly the watermark you need.