PDF Overlay – Overlay One PDF on Top of Another
Free online PDF overlay tool to superimpose, layer and stack one PDF over another. Adjust opacity, position and page alignment to put one PDF on top of another — perfect for letterheads, stamps, watermarks and signatures. 100% private: your files are processed in your browser and never uploaded. No signup, no watermark, no limits.
Upload & Configure
Drag & Drop your Base PDF here
or
Drag & Drop your Overlay PDF here
or
Preview & Download
Upload PDF files to see preview
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How to Overlay PDFs in 3 Steps
New to this? Read our full guide on how to overlay a PDF — superimpose, layer & stack documents, with 7 practical use cases.
1. Select Your PDFs
Upload your base PDF and the overlay PDF. The files are processed securely in your browser, never uploaded to any server.
2. Customize Settings
Adjust the overlay opacity, position, and page alignment to get the perfect combination of your documents.
3. Process & Download
Click "Process Overlay" and download your combined PDF. Your new document will be generated instantly for you to download.
Your Security is Our Priority
100% Private & Secure
Your PDFs are processed entirely in your browser. No files are ever uploaded to a server, guaranteeing your data's privacy.
Instant, Browser-Based
Because there are no uploads, the overlay process is instant. Your combined PDF is ready as soon as you click the button.
Completely Free
Overlay unlimited PDF files for free. No watermarks, no limits, and no registration required.
Frequently Asked Questions
Is it safe to overlay confidential PDFs with this tool?
Yes. This tool is 100% secure. All processing happens locally in your web browser. Your PDF files are never uploaded to any server, so your sensitive information remains completely private.
What's the difference between PDF overlay and PDF merging?
PDF merging combines pages from different documents sequentially, while PDF overlay places one PDF on top of another, creating a layered effect. Overlay is perfect for adding watermarks, signatures, or annotations to existing documents.
Can I overlay multiple pages from the overlay PDF?
Yes. You can choose to match pages (page 1 overlays page 1, page 2 overlays page 2, etc.), overlay the first page on all pages, or overlay only on the first page of the base document.
What file size limitations are there?
There are no specific file size limitations, but very large PDFs may take longer to process depending on your device's capabilities. For best performance, we recommend files under 100MB.
What is a PDF overlay?
A PDF overlay places the contents of one PDF directly on top of another, creating a single layered document. Unlike merging (which puts pages one after another), an overlay superimposes pages so both appear together — ideal for adding a letterhead, stamp, watermark, or signature over an existing document.
How do I overlay two PDFs on top of each other?
Upload your base PDF and the overlay PDF, set the opacity, position and page alignment, then click "Process Overlay" and download the result. The two PDFs are layered on top of each other entirely in your browser — nothing is uploaded.
Can I superimpose or layer one PDF over another?
Yes. This is exactly what the tool does — it superimposes (layers) one PDF over another. You control the transparency with the opacity slider, so you can stack documents with a faint, see-through overlay or a fully opaque one.
Can I overlay a watermark, stamp, or image-based PDF?
Yes. Any PDF can be used as the overlay layer, including a logo, letterhead, stamp, signature, or an image saved as a PDF. Lower the opacity for a watermark-style effect, or keep it at 100% to place a solid stamp on the page.
What People Usually Do Before and After an Overlay
Overlaying is rarely the whole job. These are the steps that most often sit either side of it, in the order they normally come up.
Before overlaying
If the two files have a different number of pages, or the pages are out of order, fix that first — an overlay maps page 1 onto page 1, page 2 onto page 2, and so on. Use rearrange PDF pages to reorder, remove PDF pages to drop blanks, or extract PDF pages to pull out just the range you want to stamp. To put several documents behind a single letterhead, merge the PDFs into one file first.
After overlaying
A stamped or letterheaded document usually needs finishing. Add page numbers to the PDF so the combined document paginates correctly — useful when the overlay produced a single set from several sources. Add a watermark if the file needs a DRAFT or CONFIDENTIAL marker on top of the overlay, compress the PDF when the layered result is larger than you want to email, and password-protect the PDF before sending it on.
Related reading
Branding a document? Adding a letterhead, stamp or template to a PDF covers the exact settings for applying one design across every page. For a general walkthrough, see how to overlay a PDF. If you are weighing this against a desktop tool, why files never leave your browser explains how the in-browser processing works.