Add Watermark to PDF
Stamp a text watermark on every page — diagonal or horizontal, free
100% private — Files are processed right in your browser and never uploaded to any server.
Stamping mechanics
- Placement math — diagonal marks rotate around the true page center and scale with dimensions, so A4 and Letter both center correctly.
- Opacity blending — alpha applies to fill only; edges stay anti-aliased rather than pixelated.
- CJK safety — Chinese/Japanese/Korean characters auto-embed a subsetted Noto Sans CJK; other scripts use standard fonts.
- Ranges — stamp every page or only selected ones.
Watermarks that survive printing and copying
Diagonal or horizontal text stamped into the content stream at your opacity — applied locally in seconds, no upload involved.
Text up to 60 characters
Stamp a word or phrase up to 60 characters long — DRAFT, CONFIDENTIAL, a company name — across every page. Chinese and Japanese watermark text renders through an embedded fallback font instead of empty boxes.
Diagonal or horizontal layout
Run the stamp corner to corner in diagonal orientation, or place it horizontally through the middle for a subtler mark. Gray, red, blue, and black colors cover the usual marking conventions.
Size and opacity dials
Three font sizes from 36 to 72 points and three opacity levels from 15 to 50 percent balance visibility against readability — a faint draft mark or a strong notice that is hard to ignore.
How it works
- 1
Drop in the PDF you want to watermark.
- 2
Type your text and pick a color, size, opacity and orientation.
- 3
Click Process and download your watermarked PDF.
Frequently asked questions
Can I use my own text?⌄
Yes — type anything up to 60 characters, like "CONFIDENTIAL", "DRAFT", or a company name.
Does it cover the content underneath?⌄
No — the watermark is semi-transparent (you control the opacity), so the original content stays fully readable.
Is my file uploaded?⌄
No — the watermark is drawn entirely in your browser. Your PDF never leaves your device.
Can I remove a watermark added by this tool?⌄
Not with this tool — keep your original file if you might need an unwatermarked copy later.
Related tools
What Is a PDF Watermark?
A PDF watermark is a semi-transparent label placed across every page of a document, marking who it belongs to or what state it is in. Drafts, confidential files, review copies, and anything you hand to people outside your team benefit from a visible stamp such as DRAFT, CONFIDENTIAL, or your company name. This tool draws a text watermark across the middle of each page in diagonal or horizontal orientation, with your choice of color, size, and opacity — subtle enough not to hide the content, visible enough to discourage misuse. The stamp is drawn over the existing page content, so nothing else in the document is altered.
What this tool can do
- ✍️ Write your own watermark text, up to 60 characters
- ↩️ Choose diagonal or horizontal orientation to suit the document's layout
- 🎨 Pick from gray, red, blue, or black ink
- 🔍 Set the size — small, medium, or large
- 🌫️ Control the opacity from light to strong, keeping the content readable
- 🌏 Chinese, Japanese, and Korean watermark text is supported
When you'll use it
- 📝 Mark internal drafts with a DRAFT label before circulating them
- 🔒 Label confidential or client documents before sharing them externally
- 🏢 Stamp proposals and invoices with your company name
- 📚 Put an ownership mark on e-books or course materials you distribute
Watermarks are added locally in your browser with pdf-lib — your file is never uploaded. The stamp is drawn onto each page as regular content, so everyone who receives the file sees it; this is a deterrent rather than cryptographic protection, so combine it with the password tool for truly sensitive files. Watermark text is limited to Latin or CJK scripts, and the watermark is centered on each page rather than tiled.