Add Watermark to PDF — Free Online PDF Watermark Tool

Add Watermark to PDF — Free Online PDF Watermark Tool. Add text watermarks to your PDF documents instantly. Free, private, browser-based PDF watermark tool — customize text, layout, opacity, rotation, and font without uploading your file.

Our free add watermark to PDF tool lets you stamp any text onto every page of your PDF — entirely in your browser, with nothing uploaded to any server. How to Add a Watermark to a PDF Drop or select your PDF in the upload zone.

Type your watermark text (e.g., CONFIDENTIAL, DRAFT, your company name). Choose a layout: Centered (single stamp) or Tiled Pattern (repeating grid). Adjust font, size, color, opacity, and rotation using the live-preview controls.

Click Add Watermark to download your watermarked PDF instantly. Watermark Layout Options Centered: Places one watermark in the center of each page — ideal for CONFIDENTIAL stamps, DRAFT notices, or copyright notices on slides and reports.

Tiled Pattern: Repeats the watermark across the full page in a grid — ideal for maximum coverage on sensitive documents, exam papers, or branded templates. Customization Options Set watermark text to any string up to the page width.

Choose from three built-in PDF fonts: Helvetica (sans-serif), Times Roman (serif), or Courier (monospace). Adjust font size from 12pt to 200pt, rotation from −180° to 180°, and opacity from 0% (invisible) to 100% (fully opaque).

Pick any color with the built-in color picker. A live visual preview updates in real time so you see exactly how the watermark will look before generating the file. Privacy & Security All processing runs client-side using pdf-lib.

Your PDF never leaves your device, making this tool safe for contracts, NDAs, financial statements, legal briefs, medical records, and any confidential document you cannot upload to a third-party service.

Output The watermarked file is downloaded as a PDF with a filename derived from the original (e.g., report_watermarked.pdf ). The original document is not modified. All pages receive the watermark with consistent positioning and styling.

Related Tools After watermarking you can add page numbers to your PDF , edit PDF metadata , organize PDF pages , or merge PDFs — all browser-based in the same toolbox.

Frequently asked questions

How do I add a text watermark to a PDF?

Drop your PDF on the upload area, type the text in Watermark Text (CONFIDENTIAL by default) and adjust the settings, then click Add Watermark. The watermarked copy downloads straight away using the name in Output Filename, for example report_watermarked.pdf.

What is the difference between Centered and Tiled Pattern?

Centered draws one watermark in the middle of every page. Tiled Pattern repeats the text in a grid about every 200 points across and down each page, which covers the whole page and makes the mark harder to crop out.

Which watermark settings can I change?

Rotation from -180 to 180 degrees (default -45), opacity from 0 to 100 percent in 5 percent steps (default 30), font Helvetica, Times Roman or Courier, font size from 12 to 200 points (default 48) and any text color. The on-page preview is only an approximation of the final PDF.

Why does adding the watermark fail with an error?

The watermark uses the standard PDF fonts Helvetica, Times Roman and Courier, which only cover basic Latin characters, so text in scripts such as Chinese, Arabic or Cyrillic, or emoji, cannot be encoded. Password-protected PDFs also cannot be opened. Use Latin text and an unlocked PDF.

Is my PDF uploaded to a server?

No. The watermark is drawn into the PDF with the pdf-lib library in your browser and the result is saved directly to your device. The same text and settings are applied to every page of the document.

How to use this online tool

Add Watermark to PDF — Free Online PDF Watermark Tool is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

Add Watermark to PDF — Free Online PDF Watermark Tool keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use Add Watermark to PDF — Free Online PDF Watermark Tool for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.