Add Watermark to PDF
Stamp a text watermark across every page of a PDF file. Upload a PDF, customize the text, size, and opacity, and download the watermarked document.
Click to upload a PDF file
Your file is processed entirely in your browser
Recommended Settings
Pro Tips
- •Diagonal position runs the watermark corner-to-corner across the page, which is harder to crop out than a horizontal stamp
- •Lower opacity (15-30%) keeps the underlying content readable, while higher opacity makes the watermark more prominent
- •The same watermark text and style is applied to every page in the document
- •The whole file is processed locally in your browser using pdf-lib - nothing is uploaded anywhere
Most Popular
Most users use a diagonal watermark at 30% opacity with text like DRAFT or CONFIDENTIAL
When to Use This Tool
Stamp DRAFT across a document that's still being reviewed, so readers know it isn't the final version.
Add your name or organization as a watermark to discourage unauthorized copying or redistribution of a PDF.
Mark sensitive documents as CONFIDENTIAL or INTERNAL USE ONLY before sharing them with a limited audience.
Watermark a sample or preview PDF with SAMPLE to prevent it from being mistaken for a purchasable final product.
How It Works
Read the uploaded PDF file as binary data directly in your browser
Load the file into a PDF document using the pdf-lib library and embed a bold Helvetica font
For each page, calculate the watermark's position and rotation angle based on the page's dimensions
Draw the semi-transparent watermark text onto every page at the selected size and opacity
Save the modified PDF and trigger a download
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by pdf-lib for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
Can I remove a watermark added by this tool later?
Watermarks added this way are drawn directly onto the page content, similar to how most watermarking tools work, so they can't be removed with a simple toggle - you'd need to start from the original unwatermarked file.
Does the watermark cover up the existing content?
The watermark is drawn on top of the existing page content, but at a low opacity by default so the underlying text and images remain readable through it.
Can I use a custom color for the watermark?
This tool uses a neutral gray watermark color to keep it visible without being too distracting. Custom color selection isn't currently supported.
Is my PDF uploaded to a server?
No. The entire file is read, watermarked, and re-saved locally in your browser using the pdf-lib library. Your document never leaves your device.
Does the watermark position adjust for different page sizes?
Yes. The watermark's position and rotation angle are calculated based on each page's actual width and height, so it's centered correctly even in documents with mixed page sizes.