Should I pick background or foreground?

Letterhead and templates: background, so your document's text renders over them naturally. Stamps and marks that must remain visible regardless of what's on the page: foreground. When unsure, try background first — it's the right answer for most layering jobs.

My foreground overlay hides the document. Why?

The overlay page has an opaque white background, which covers everything beneath it in foreground mode. Either switch to background mode (the white sits behind your content instead), or rebuild the overlay source with no background fill.

What if the overlay has fewer pages than the document?

It cycles. A one-page overlay stamps every page; a two-page overlay alternates — useful for distinct odd/even letterhead. If the overlay is longer than the document, the surplus overlay pages go unused.

What if the two PDFs have different page sizes?

The overlay is scaled to fill each content page, so mismatched sizes work — though an overlay designed for a very different aspect ratio will stretch. For best results, author the overlay at the same page size as the document.

Overlay PDF

Overlay one PDF on top of another as a background or foreground layer. Files are processed entirely in your browser.

Drop PDF files here or browse

Max 100MB per file · Up to 2 files

About Overlay PDF

An overlay combines two PDFs page-on-page: one supplies the content, the other a layer applied to every page. The classic use is letterhead — a one-page PDF with your logo, address, and footer rule, applied beneath a plain document so every page looks like it was printed on company stationery. The same mechanism handles stamps (PAID, APPROVED, RECEIVED), watermark artwork too elaborate for plain text, and form backgrounds.

Convertora gives you the choice that matters: whether the overlay goes behind the content or in front of it. Background mode slips the letterhead genuinely beneath the existing page — your document's text renders on top of it — while foreground mode lays the stamp over everything. Most overlay tools only manage 'on top'; placing a layer underneath existing content is the trick that makes letterhead work properly.

The overlay is stretched to match each content page exactly, and a short overlay repeats in a cycle: a one-page letterhead applies to every page of a fifty-page document automatically.

How to use it

1Upload the content PDF first — the document itself.
2Upload the overlay PDF second — the letterhead, stamp, or background. One page or many.
3Choose Background (overlay beneath the content — right for letterhead) or Foreground (overlay on top — right for stamps).
4Click Apply. Each content page is paired with an overlay page, cycling through the overlay if it's shorter, and the layers are combined at full page size.
5Download the result, saved with an -overlay suffix.

Common use cases

Applying company letterhead to contracts and letters generated as plain PDFs.
Stamping PAID or APPROVED across invoices in a way that sits over the content.
Adding a recurring background — a watermark graphic, a draft banner, a form template — to every page.
Branding reports from systems that can't produce letterhead themselves.

Frequently asked questions

Tips

Build letterhead by exporting a one-page PDF from the same template your printed stationery uses — Word, Google Docs, or your design tool all export PDF.
For a simple diagonal text stamp like CONFIDENTIAL, the Watermark PDF tool is the quicker route; reach for Overlay when the artwork is more than a line of text.

100% private — runs in your browser

Convertora processes everything on your device using JavaScript and WebAssembly. Files never leave your browser, are never uploaded to a server, and are never seen by us or anyone else. The moment you close the tab, the data is gone — there is no temporary cloud copy, no log entry, no retained backup.

Because the work happens locally, processing speed depends on your device — but there are no rate limits, no daily caps, and no file size restrictions beyond what your browser can handle in memory. No signup, no account, no payment. The tool works the same in incognito mode, on a corporate network, or after the page has loaded once, even with the network disconnected.