PDF Watermark Adder
Stamp text diagonally across a PDF's pages — applied to every page by default, or a specific selection. Opacity, font size, and rotation angle are all adjustable, from a subtle background stamp to an unmissable overlay. The watermark is drawn directly onto each page as real content, becoming a permanent part of the output. Runs entirely client-side using pdf-lib — nothing is uploaded.
About this tool
This tool stamps text diagonally across a PDF's pages — the classic "CONFIDENTIAL" or "DRAFT" treatment — applied to every page by default, or a specific selection you choose. Opacity, font size, and rotation angle are all adjustable, so the watermark can be subtle (low opacity, behind the content) or unmistakable (high opacity, on top) — and a live preview, rendered right on your actual first page, updates instantly as you move any slider, so you see exactly what you're getting before downloading anything. The watermark is added as real text drawn directly onto each page, not a separate overlay layer, so it becomes a permanent part of the page content in the output file. It runs entirely client-side using pdf-lib and pdf.js — nothing you upload is ever sent anywhere.
What you can do
- Stamp text diagonally across every page, or just the ones you choose
- Adjustable font size, opacity, and rotation angle — with a live preview on your actual page
- Download the watermarked PDF with one click
- Nothing is uploaded — everything runs locally in your browser
How to use
Step 1
Upload a PDF and set your text
"CONFIDENTIAL", "DRAFT", a company name — whatever you need stamped.
Step 2
Adjust size, opacity, and angle
Watch the live preview update instantly — no need to download and check.
Step 3
Apply and download
Every selected page gets the watermark, roughly centered.
Example
A contract draft:
Watermark
Text: "DRAFT" · Opacity: 20% · Rotation: 45°
stamps a large, semi-transparent, diagonal "DRAFT" across every page — visible at a glance, but not obscuring the underlying text.
How your data is handled
This tool is labeled 🟢 Browser: your PDF is watermarked directly in your browser using the pdf-lib library — nothing is uploaded to a server, and nothing about it is retained once you leave the page.
Frequently asked questions
Does the preview show exactly what I'll get?+
It's a close, live approximation rendered right on your actual page — font size, opacity, and rotation all match — but rotation pivots around the text's visual center in the preview versus its baseline start point in the real output, so at extreme rotation angles the exact position can differ very slightly. The text content, size, and opacity are accurate.
Can I apply the watermark to only some pages?+
Yes — uncheck "Apply to every page" and enter a page range like 1-3,5 to watermark only those pages. The preview automatically shows the first page in that selection.
What opacity should I use?+
Lower opacity (10-30%) keeps the watermark subtle and the original content fully readable underneath — good for a background "DRAFT" stamp. Higher opacity makes it much more prominent, useful when the watermark itself needs to be unmissable.
Can I remove a watermark added by this tool?+
Not with this tool — the watermark is drawn directly onto the page as real content, the same as any other text on the page, so it isn't a separate, removable layer.
Does watermarking affect the rest of the page content?+
No — the original content is untouched; the watermark text is simply drawn on top of (or visually behind, depending on opacity) the existing page content.
Is my PDF uploaded anywhere?+
No — it's watermarked directly in your browser using the pdf-lib library. Nothing here ever leaves your device.