PDF Watermark
100% Private & Local — Your files NEVER leave your device

PDF Watermark

Add a text watermark to every page of your PDF. Runs entirely in your browser — files never leave your device.

Drop your PDF here

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Max 200 MB

Supports PDF files up to 200 MB

Why Add a Watermark to Your PDF?

Watermarks serve both legal and practical purposes. A "CONFIDENTIAL" or "DRAFT" stamp on every page makes it immediately clear that a document shouldn't be shared externally. For contracts, proposals, or internal memos sent to clients, a visible watermark discourages unauthorized redistribution and clearly marks which version of a document is in circulation. Photographers use watermarks to protect previews sent to clients before final payment.

Unlike most online watermark tools — which require you to upload your PDF to a remote server — this tool processes everything locally inside your browser using pdf-lib, a powerful open-source PDF library. Your document never leaves your device. No file size limit imposed by us. Works offline once loaded.

Frequently Asked Questions

Does this tool upload my PDF anywhere?
No. Your PDF is processed entirely within your browser using the pdf-lib JavaScript library. Nothing is transmitted to any server. You can verify this by opening your browser's DevTools → Network tab while processing — you will see zero outbound file upload requests.
What watermark styles are available?
Three styles are supported. Diagonal places the watermark text at a 45° angle across the center of each page — the most visible and hardest to overlook. Center places the text horizontally in the middle of each page. Corner adds a small, subtle watermark in the bottom-right corner of each page.
Can I customize the opacity and color?
Yes. The opacity slider ranges from 10% to 80%. For most documents, 20–30% is unobtrusive but visible. For color, you can choose Gray (neutral, works on all backgrounds), Black, Red (assertive, great for "CONFIDENTIAL"), Blue, or any custom color using the color picker.
Will the watermark appear on every page?
Yes. The watermark is applied to every page of the PDF, regardless of page count. The position and size are automatically calculated based on each page's dimensions, so the watermark scales correctly even if the PDF has mixed page sizes.
Does this work with password-protected PDFs?
Password-protected PDFs with edit restrictions cannot be processed — you'll need to remove the password first using the original application that created the PDF. Open PDFs (including those with no password) work perfectly.
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