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Watermark PDF — Free Online
Stamp custom text on every page of your PDF — choose position, opacity, and content. No signup, no page limits on output, nothing added except the watermark you set.
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or browse to upload · PDF only · max 20 MB · max 20 pages
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PDF Watermarking Explained
Visible marks, honest expectations
A text watermark stamps each page at the render layer — it discourages casual redistribution and flags a document’s status (DRAFT, CONFIDENTIAL, FOR REVIEW). It doesn’t cryptographically prevent copying. For documents leaving your organization, pair a visible watermark with PDF access controls or link-expiry if hard restrictions matter.
What happens under the hood
Upload any non-password-protected PDF and the tool rasterizes each page using Ghostscript, annotates the watermark text at your chosen position and opacity using ImageMagick’s annotateImage function, then recomposes the pages into a downloadable PDF. The whole process is server-side and temporary — your file is deleted as soon as your download starts.
Choosing the right position
Diagonal is the standard for CONFIDENTIAL or DRAFT stamps. It crosses the readable content at a 45° angle and is clearly visible at a glance without a reader having to look for it. Center works well for copyright notices on single-page certificates or invoices. Corner positions (Top-Left, Bottom-Right, etc.) suit subtle reviewer attribution or brand tags on documents where a diagonal would obscure the main body content.
Opacity: what actually works
30–50% gives a semi-transparent watermark that’s clearly visible without making the document hard to read — the right range for most professional use. 70–100% is for cases where the mark must be unmissable: sample copies of stock documents, proof pages, or screenshots intended for social sharing. Below 20%, the watermark may become too faint to survive printing or low-resolution screen captures.
Rasterizing trade-offs
This tool converts each page to a raster image before stamping the overlay. This increases file size slightly compared to vector text-layer watermarking and may reduce sharpness on documents with very fine typography when viewed at high zoom. For most business documents (reports, presentations, contracts) the output is perfectly readable. For archival or print-critical PDFs, a local tool like Acrobat or qpdf’s text-layer approach will preserve fidelity better.
Frequently asked questions
Can I add an image watermark instead of text?
Not yet — this tool supports text-only watermarks. Image watermarks (logos, signatures, stamps) are planned for a future update. For image watermarks today, GIMP, PDF-XChange Editor, or Acrobat Pro handle them natively.
Will the watermark appear on every page?
Yes. The watermark is applied to every page in the uploaded PDF. If you need to stamp specific pages only, use the Split PDF tool first to extract those pages, watermark them, then merge the result back together.
Is my file stored after I download the result?
No. Your file is deleted from our server automatically as soon as the download completes. We don’t analyze, store, or share your documents. Processing is temporary and session-scoped.
Why can’t I watermark a password-protected PDF?
Rendering a password-protected PDF requires the owner password — and we don’t ask for it. Remove the password first using Acrobat (File › Properties › Security › No Security), PDF24 Tools, or the command-line tool qpdf --decrypt input.pdf output.pdf.
What is the 20-page limit?
Each page is rasterized server-side, which takes CPU time and memory. The 20-page cap keeps processing fast (typically 5–15 seconds) for everyone using the tool. For longer documents, the same task runs in seconds locally with ImageMagick: convert -density 150 input.pdf -fill "rgba(128,128,128,0.4)" -gravity Center -annotate 45 "CONFIDENTIAL" output.pdf
Can I choose a custom font, size, or color?
The current version uses a clean bold sans-serif rendered in white with a dark stroke for legibility on any background — light, dark, or patterned pages. Custom font, size, and color options are on the roadmap. The default style works well on the vast majority of business documents.
How to add a watermark to a PDF
Upload your PDF by dragging it onto the upload area or clicking “Browse files.” The file must be under 20 MB, not password-protected, and 20 pages or fewer.
Type your watermark text — a copyright notice, status label (DRAFT, CONFIDENTIAL), reviewer name, or any text up to 100 characters.
Set the opacity and pick a position. Diagonal is the default and suits most use cases. Corner positions work better for subtle labels.
Click “Add Watermark.” Processing takes a few seconds. Download your watermarked PDF when the button appears.