PDF Overlay

Overlay or underlay pages from one PDF onto another.

Upload base PDF

Upload overlay/underlay PDF

Your files never leave your device.

How It Works

1

Upload Two PDFs

Upload your base PDF and the PDF you want to overlay or underlay.

2

Choose Mode

Select overlay (on top) or underlay (behind). Optionally set a page range and repeat.

3

Download

Download your PDF with the overlay or underlay applied.

Frequently Asked Questions

How do I apply the overlay to only some pages?

Type a range in the Apply to pages field using the base document's page numbers, for example 1-5, 8, 10-z, where z stands for the last page. Leave it empty to cover every page.

What happens when the two PDFs have different page counts?

With the loop option on, the overlay's pages repeat in order until every base page is covered, so a 2-page overlay on a 5-page document is applied as 1, 2, 1, 2, 1. With it off, pages are matched one to one and base pages beyond the overlay's length are left unchanged.

Do the page sizes need to match?

No. An overlay page larger than the base page is scaled down to fit and a smaller one is centered without being enlarged. There are no controls for position, scale, or opacity, so build the overlay PDF at the size and transparency you want before combining.

Does the base PDF stay searchable and editable?

Yes. The base document's text, links, form fields, and bookmarks are untouched; the overlay is added to each page as an extra drawing layer, and any text in it remains selectable too.

Are links, form fields, or comments from the overlay PDF copied over?

No. Only the visible page content of the overlay is used. Annotations on the overlay pages, including links, form fields, and comments, don't transfer to the result.

Which mode should I use for a letterhead?

Underlay, so the letterhead sits behind the page content, with the loop option on if the letterhead is a single page. For text or image watermarks with adjustable opacity, rotation, and placement, Add Watermark gives more control.

Why does it fail on a password-protected PDF?

The tool doesn't ask for passwords. If either file needs a password to open, remove it first with the password removal tool, then apply the overlay to the copy without the password.

Do both PDFs get uploaded?

No. The overlay is applied by qpdf compiled to WebAssembly, which runs entirely in your browser, so neither the base document nor the overlay file leaves your device. The combined PDF downloads under the base document's filename.