pdfcosmos

Overlay PDF

Stamp a letterhead, watermark, or title block from one PDF onto another.

Free, fast, and privacy-first.

Add the base PDF

The document you want to stamp

or drag & drop a PDF here

PDF files only · one file at a time · up to 100 MB

Overlay one PDF on another — letterhead, watermark, or title block

Overlay PDF stamps one PDF onto every page of another. Choose your base document and a “stamp” PDF — a designed letterhead, a watermark, a title block, or DRAFT/CONFIDENTIAL artwork — and it's applied across the whole base. This is how you brand a document with a real, designed overlay rather than plain text: a letterhead on every page of a report, a title block on CAD drawings, or a graphic watermark over a contract.

You choose overlay or underlay: overlay draws the stamp on top of each page (right for watermarks and stamps), while underlay draws it behind the content (right for letterheads and backgrounds, so the page's text stays on top and readable). If the stamp PDF has fewer pages than the base, its last page is repeated across the rest — so a one-page letterhead lands on every page automatically. Both files are read with pdf.js and combined with qpdf, entirely in your browser, so your files never leave your device. Unlock a password-protected PDF first.

  • A designed overlay, not text

    Stamp a real letterhead, watermark, or title block PDF across every page.

  • Over or under the page

    Overlay for watermarks and stamps; underlay for letterheads, so text stays on top.

  • One-page stamp, every page

    If the stamp is shorter, its last page repeats across the whole base document.

  • Nothing is uploaded

    pdf.js and qpdf combine the files in your browser. Your files never leave your device.

How to overlay one PDF on another

  1. Add both PDFs

    Choose the base PDF (the document) and the stamp PDF (the letterhead, watermark, or title block).

  2. Overlay or underlay

    Pick whether the stamp goes over the page (on top) or under it (behind the content).

  3. Stamp and download

    Click “Stamp PDF”. The stamp is applied to every page and the new PDF downloads, all in your browser.

Frequently asked questions

Are my PDF files uploaded to a server?
No. Both PDFs are read and combined entirely in your browser (pdfjs to read, qpdf to stamp). Your files never leave your device. You can confirm it in your browser's Network tab.
What can I use this for?
Applying a letterhead or branding to every page, adding a title block to CAD drawings, watermarking with a designed PDF (rather than plain text), or stamping “DRAFT”/“CONFIDENTIAL” artwork across a document.
What if the stamp has fewer pages than the base?
The last page of the stamp is repeated across the remaining base pages. So a one-page letterhead is applied to every page of the base automatically.
What's the difference between overlay and underlay?
Overlay draws the stamp on top of each page (good for watermarks and stamps). Underlay draws it behind the page content (good for letterheads and backgrounds, so text stays on top).
Can it stamp a password-protected PDF?
No. Unlock it first (with the Unlock PDF tool), then overlay. Encrypted files can't be read without the password.
Is Overlay PDF free?
Yes, it's completely free to use, with no sign-up and nothing to install.