How to Overlay a PDF: Superimpose, Layer & Stack Documents
Need to put one PDF on top of another — to stamp a logo, drop on a watermark, add a signature, or place a document over a letterhead? That's a PDF overlay: superimposing (layering) the contents of one PDF onto another so both appear together. Here's exactly how to do it, free and privately, in your browser.
What does it mean to overlay a PDF?
Overlaying a PDF means placing the pages of one PDF directly on top of another, like transparent sheets stacked together. People describe the same action many ways — superimpose a PDF, layer PDFs, stack PDFs, put one PDF on top of another, or overlap two PDFs. It's different from merging, which simply places pages one after another. An overlay combines them into the same page.
How to overlay one PDF on top of another (step by step)
- Open the PDF Overlay tool. (Tip: disconnect your internet first — it still works, proving nothing is uploaded.)
- Add your base PDF (the document underneath) and your overlay PDF (the layer that goes on top).
- Set the opacity — lower it for a faint, see-through watermark, or keep it at 100% for a solid stamp.
- Choose the position (center or a corner) and the page alignment — match pages 1-to-1, overlay the first page onto every page, or overlay only the first page.
- Click Process Overlay, preview the result, and download. The PDFs are layered locally on your device.
7 practical ways to use a PDF overlay
Letterhead & branding
Place a plain document over your company letterhead or branded template in one step.
Watermarks
Drop a "Confidential" or "Draft" PDF over each page at low opacity. (Or use Add Watermark.)
Stamps & seals
Overlay an "Approved", "Paid", or notary-style stamp saved as a PDF.
Signatures
Layer a signature PDF onto a contract. For drawn/typed signing, see Sign PDF.
Logos & images
Overlay a logo or image (saved as a PDF) onto every page of a document.
Forms over backgrounds
Place filled form content on top of a fixed background or template layout.
Comparison & tracing
Superimpose two versions to eyeball differences. For precise diffs, use Compare PDFs.
Overlay vs. merge vs. watermark — which do you need?
| You want to… | Use |
|---|---|
| Put one PDF's content on top of another's page | PDF Overlay |
| Join PDFs end to end into one longer file | Merge PDF |
| Add repeating text/image stamp across pages | Add Watermark |
| Add a drawn or typed signature | Sign PDF |
Tips for a clean overlay
- Match page sizes. Overlays line up best when the base and overlay pages are the same dimensions.
- Use opacity intentionally. ~20–40% reads as a watermark; 100% reads as a solid stamp or letterhead.
- Pick the right alignment. "Overlay first page on all" is ideal for branding every page with one template.
- Keep it private. Because processing is in-browser, even confidential contracts never leave your device.
Overlay your PDFs now
Free, private, no signup — superimpose, layer or stack your PDFs directly in your browser:
Open the free PDF Overlay tool →
Related tools:
See also: Overlay documents with templates & letterheads.
Frequently asked questions
How do I overlay two PDFs on top of each other?
Open the PDF Overlay tool, add a base PDF and an overlay PDF, set the opacity and position, then click Process Overlay and download. The two files are layered on top of each other in your browser.
What's the difference between overlaying and merging PDFs?
Overlaying superimposes one PDF onto the same page as another (layered). Merging places pages sequentially, one after the other, into a single longer document.
Can I overlay an image or logo onto a PDF?
Yes. Save the image or logo as a PDF and use it as the overlay layer. Adjust the opacity for a watermark effect or keep it solid for a stamp.
Is it private to overlay confidential PDFs online?
Yes. The overlay happens entirely in your browser, so your files are never uploaded to a server. You can confirm it by running the tool with your internet disconnected.