PDF tool
Add a watermark to a PDF
Stamp a word across every page — DRAFT, CONFIDENTIAL, a client name — at whatever angle, colour and transparency you choose. The text is sized from each page's own dimensions, so it looks the same on A5 and A3.
- 100% free
- No signup
- Never uploaded
Drop your file here
or click to browse from your device
Supports PDF · Max 100 MB · Up to 3,000 pages
Settings
Latin letters, digits and common punctuation only — the fonts built into PDF cannot draw Vietnamese diacritics, Cyrillic or CJK.
Around 20% stays readable underneath. Above 60% the text below becomes hard to read.
Leave as "all", or narrow it down like 1-3, 8, 12-.
- Secure & privateYour files are never shared
- Lightning fastMost images in under a second
- High qualitymozjpeg and libvips under the hood
- Works everywhereAny device, any browser
Output quality
The watermark is real vector text drawn over the existing page content, so it stays perfectly sharp at any zoom level and adds almost nothing to the file size. Nothing underneath is altered — the original text remains selectable and searchable, and images are untouched. Size is derived from each page's diagonal so that the stamp covers roughly the same proportion of every page, which is why it looks consistent in a document that mixes portrait and landscape sheets. Because it is drawn as text rather than baked into the page, it can also be removed again by software that edits PDF content; treat it as a label, not a lock.
See what this tool actually did to real files — median size change, speed and sample size, published whichever way the numbers fall.
Privacy: this tool does not upload your file
The file is never sent anywhere
This tool is JavaScript running in your tab. Your document is read from your disk into browser memory and never transmitted — not to us, not to anyone. It handles files up to 100 MB and 3,000 pages.
You can check this yourself
Load this page, turn off your internet connection, and run the tool. It still works. That is not a promise about our conduct — it is something you can verify in ten seconds.
Nothing to delete afterwards
There is no upload, no job record and no copy on any server, so there is no retention period. Close the tab and the working copy is gone with it.
No third parties involved
The PDF engine and its fonts are served from this domain rather than a public CDN, so no outside company sees that you used this page, or when.
Input, output and limits
Every figure below is read from the same configuration the server enforces, so this page cannot promise a limit the system will refuse.
- Input formats
- application/pdf
- Output format
- application/pdf
- Maximum file size
- 100 MB per file
- Maximum pages
- 3,000 per run
- Multiple files
- One file at a time
- Price
- Free, with no account and no watermark
- Processing
- Inside your browser — the file is never uploaded
- Engine
- pdf-lib, running inside your browser
- File retention
- None — nothing is uploaded, so there is nothing to keep or delete
Common use cases
Marking a document as a draft
A visible DRAFT across every page prevents the common and expensive mistake of an unfinished version being acted on as final.
Labelling something confidential before sharing
It sets expectations clearly and creates a record of what the recipient was told, even though it enforces nothing.
Tagging copies sent to different people
Putting each recipient's name on their copy makes it obvious where a leaked document came from.
Settings you can change
Watermark text
Default: CONFIDENTIAL.
Latin letters, digits and common punctuation only — the fonts built into PDF cannot draw Vietnamese diacritics, Cyrillic or CJK.
Opacity (%)
From 5 to 100, default 20.
Around 20% stays readable underneath. Above 60% the text below becomes hard to read.
Colour
Default: #ff0000.
Angle (°)
From -90 to 90, default 45.
Which pages
Default: all.
Leave as "all", or narrow it down like 1-3, 8, 12-.
Troubleshooting
- It refused my text
- It contains characters the built-in PDF fonts cannot draw — accented Vietnamese, Cyrillic, Greek or CJK. The message names the specific characters. Rewording without them is the only option here.
- The watermark hides the content
- Lower the opacity. 15–25% is usually right; anything above 60% competes with the text underneath.
- It looks too small or too large
- Size follows the length of your text — the whole phrase is fitted across the page diagonal, so a long sentence renders small. Shorter words appear larger.
- Someone removed the watermark
- Expected. It is drawn text, not protection. Nothing that keeps a document readable can also stop it being edited.
Something else went wrong? Tell us what happened — a person reads every report, and that is how this list gets longer.
Frequently asked questions
Browse pdf toolsCan I use Vietnamese, Chinese or Cyrillic text?
No, and the tool stops you rather than producing boxes. Watermarks are drawn with the fonts built into the PDF format itself, which only cover the Latin alphabet, digits and common punctuation. Embedding a full Unicode font would mean sending several hundred kilobytes of font data to everyone who visits the page, for something most people do not need.
Does the watermark stop people copying the document?
No. It is text drawn on top of each page — visible, and removable by anyone with the right software. It marks a document as a draft or as confidential; it does not secure it. Anyone who tells you a watermark is protection is selling something.
What opacity should I use?
Around 20% is the usual balance: clearly visible, still readable underneath. Above about 60% the text below becomes genuinely hard to read, which is occasionally the intent but usually a mistake.
Can I watermark only some pages?
Yes — leave the pages box on "all", or name the ones you want, such as 1 for a cover page only.
Where does my file go when I use this tool?
Nowhere. This tool is JavaScript that runs inside your browser tab, so the file is read straight from your disk into memory on your own device and never sent to us. There is no upload, no job record and no copy to delete afterwards — close the tab and the working copy goes with it. You can confirm this yourself: load the page, disconnect from the internet, and the tool still works. It handles files up to 100 MB and 3,000 pages, and those limits come from what one browser tab can hold rather than from anything on our side.