PDF Overlay

Overlay PDFs, e.g. to combine documents with a digital paper.

Free
Private
No limits
No upload

Documents

The PDFs you want to stamp

... or drop files here

Overlay / Underlay

The PDF laid onto every page

... or drop files here

Files never leave your device

Add at least one document.

Frequently asked questions

What is a PDF overlay good for?

Anything that has to appear on every page: company letterhead or digital stationery, a background image, a stamp, a watermark, or a form template your content sits inside.

What is the difference between overlay and underlay?

An overlay is painted on top of your page, so it can cover the text underneath. An underlay is painted behind it, so your document's text and images always stay readable — that's the right choice for letterhead and backgrounds.

My overlay file has several pages. Which one is used?

You choose. 'First page on every page' repeats page 1 throughout, 'Repeat all pages in a loop' cycles through them, and 'One page each, then stop' pairs them up one-to-one and leaves the remaining document pages untouched.

Can I make the overlay semi-transparent?

Yes, the opacity slider goes from 5% to 100%. Lowering it turns any PDF into a watermark that lets the page underneath show through.

Are links and form fields kept?

Yes, your documents are stamped in place, so links, form fields and annotations all survive. Only the overlay's own appearance is added.

Is my file uploaded to a server?

No, the overlay is applied entirely in your browser and your PDFs never leave your device.

How is overlaying different from merging?

Merging puts documents one after another, so a 10-page and a 5-page file give you 15 pages. Overlaying stacks them, so the same two files give you 10 pages with the second document's content painted onto them. Use merge for sequence, overlay for letterhead, stamps and backgrounds.

Should I put the stamp over or under?

Under for letterhead, backgrounds and borders, so the base document's text stays readable on top. Over for stamps, logos and approval marks that are meant to sit on the content. Note that under fails if the base pages have an opaque white background, since it will hide the layer beneath — test one page first.

My overlay isn't visible. What went wrong?

Usually one of two things: the stamp was placed underneath a base page that has an opaque background, or the stamp PDF itself has a white background rather than a transparent one and is covering what it should show through. Try switching over/under to work out which.

What if the two documents have different page counts?

The output always matches the base document's page count. A single-page stamp is applied to every page. A multi-page stamp either repeats cyclically or maps one to one, depending on the setting, and any stamp pages beyond the base document's length are unused.

Can I use this to add letterhead to a generated report?

Yes — that is the main use. Put the report in as the base, the letterhead as the stamp, choose under so the report text stays on top, and keep the scaling at original size if both are the same paper size. One pass brands the whole document without regenerating it.

Overlaying combines two PDFs by stacking them rather than joining them end to end. One document supplies the pages; the other is painted onto those pages, either over the existing content or underneath it. Merging puts documents in sequence; overlaying puts them on top of each other.

The classic use is letterhead. A report generated by some system arrives as plain pages, and the company template — logo, address block, footer rules — is a separate one-page PDF. Overlaying the template underneath the report gives you a properly branded document without regenerating anything.

The same mechanism covers stamps, approval marks, background textures, pre-printed forms and certificate borders. Everything is composited in your browser with nothing uploaded, and both source files are left untouched.

How to overlay one PDF on another

Add the base document
This is the PDF that supplies the pages — the report, the contract, the form. The output has exactly this document's page count.
Add the stamp document
The PDF to be painted onto those pages: a letterhead, a logo, an approval stamp, a border.
Choose over or under
Over draws the stamp on top of the existing content — right for stamps and marks. Under draws it behind, so the base document's text stays fully legible on top of it — right for letterhead and backgrounds.
Set the scaling and repetition
Decide how the stamp is sized against each page, and how a multi-page stamp is distributed across the document.
Composite and download
The result is built locally and downloaded. Both originals are unchanged.

Over or under

Over: The stamp is drawn on top. Anything opaque in it hides what is underneath, so this is right for approval stamps, PAID marks, signatures and logos placed in whitespace — and wrong for a full-page letterhead, which would cover the text.
Under: The stamp is drawn behind the page's own content, which stays fully readable on top of it. This is what letterhead, watermark backgrounds, pre-printed forms and certificate borders need. The caveat is that a base page with an opaque white background will hide the layer beneath it entirely — a common surprise, and the reason to test on one page first.

Scaling the stamp to the page

The stamp and base rarely have identical dimensions, so how the difference is resolved is worth choosing deliberately.

Original size: The stamp is placed at its own dimensions, unscaled. Correct when both documents are the same paper size, which is usually true of letterhead designed for the job.
Fit: Scaled proportionally until it fits within the page, keeping its aspect ratio. Nothing is distorted or cropped, but a mismatch in proportion leaves space on two sides.
Stretch: Scaled to fill the page exactly, disregarding proportion. Fine for abstract backgrounds and textures; visibly wrong for anything containing a logo or text.

Spreading a multi-page stamp

A one-page stamp is applied to every page of the base document, which covers letterhead and most stamping.

When the stamp file has several pages, they can either repeat cyclically — page 1 of the stamp on base pages 1, 3, 5 and page 2 on 2, 4, 6, which is how a distinct first-page letterhead and continuation sheet are handled — or map one to one, stamp page 1 onto base page 1 and so on, stopping when the stamp runs out.

The output always has the base document's page count. The stamp never adds pages; if it has more pages than the base, the extras are simply unused.

Overlay, watermark or merge?

Use Add watermark if the mark is text you want to type — DRAFT, CONFIDENTIAL, a name. It is faster and gives direct control over opacity, angle and tiling without needing you to produce a PDF first.

Use PDF Overlay when the thing being applied is a designed artefact that already exists as a PDF: a letterhead with a logo and rules, a certificate border, a scanned stamp, a pre-printed form.

Use Merge PDF when the documents should follow one another rather than sit on top of one another.

One practical note on transparency: a stamp PDF with a genuinely transparent background composites cleanly in either direction. One exported with a white background will hide whatever it covers when placed over, and be hidden when placed under. If a stamp isn't behaving, an opaque white rectangle in it is almost always the reason.

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