How to Overlay One PDF on Another (Stamp, Letterhead, Watermark)
Stamp a PDF onto another in your browser — every page or a range, with position presets, PDF-point offsets and opacity. Learn what an overlay really does, and what it does not do.
What overlaying actually does
An overlay takes one PDF page and draws it on top of a page in another document. In PDF Overlay the stamp page is embedded into each target page as a form object and painted above the base page's content, so it travels with the page: an ordinary reader cannot select the stamp and delete it to reveal what is underneath, the way they can with an annotation added by an editor.
It is not a merge. The two documents are not joined into a single reading flow, nothing is renumbered, and the base keeps its page count, text, links, annotations and form fields exactly as they were. The stamp sits above the base content; the base content itself is untouched. If you want pages combined into one long document, that is PDF Merge's job.
Position, offsets and opacity
Eight presets cover the usual cases: stretch the stamp across the whole page, or fit it to the page and anchor it centre, or to the top or bottom of the left, centre or right. Every preset except stretch scales the stamp to fit the page with its aspect ratio kept, so the shorter side sits flush with the page edge — which means a small logo is enlarged to fill the sheet. That is usually what you want for a watermark or a letterhead, and it is worth knowing before you wonder why a 200-point logo came out page-sized.
The X and Y offsets nudge the anchored stamp in PDF points, positive right and up, and opacity runs from a faint 5% watermark to solid 100%. Opacity is one constant transparency applied to the whole stamp, not a fade across the page, and it never makes the content underneath translucent. The first page you are about to stamp renders as a live preview with a readout of the real geometry in points, so you can see the result before exporting. If a stamp would hang over an edge the preview says it will be cropped; if it would fall completely off the page the run is refused and names the page, so you never download a silently blank result.
Stamping every page, or just some
The default is every page. Switch to a page range and type numbers and ranges — 1-3,7 stamps pages 1, 2, 3 and 7 — and the tool validates as you type, showing you exactly which pages were selected and refusing a page past the end of the document. This is how you stamp an approved mark on the signature page of a contract, or a confidentiality footer on everything except the annexes.
For a multi-page stamp, cycle mode pairs base page 1 with stamp page 1, base page 2 with stamp page 2, and wraps around when the stamp runs out, so a two-page stamp alternates across the base. First-page-only mode repeats one stamp everywhere. Every target page is measured against its own visible box, so a document that mixes portrait and landscape pages keeps each page's own proportions, and a page with a non-zero CropBox origin is stamped relative to the part of the page a reader actually sees. Placement is written in the page's own unrotated coordinates, which means a scanned page carrying a 90 or 270 degree page rotation turns its stamp along with the text on it — the stamp behaves like the page's own content rather than fighting it.
The honest limit: stamp text stays readable
An overlay is a real stamp, not a picture of one. If the stamp PDF contains real text — a typed DRAFT or a letterhead drawn in your word processor rather than exported as an image — that text is embedded as page content and stays visible, extractable and searchable in most readers. You can usually select it, copy it, and find it with in-document search. That is correct behaviour for a stamp, and it is exactly why an overlay is the wrong tool for concealing information.
It is not a way to hide content. The base page underneath is completely unchanged, so anything the stamp covers is still there to be read, selected or found by search. To conceal text, use PDF Redact to stamp black boxes into the page, or PDF Flatten to rasterize every page into an image. And because an overlay is a working mark rather than a forensic seal, treat it as a visible, accountable mark on a page — not as tamper protection.
Limits, and what to do about them
Each file can be up to 100 MB and 200 pages, and the tool checks both before it starts rather than failing halfway through. Password-protected PDFs are outside its scope: remove the password with PDF Unlock, then stamp. A stamp that is itself a scanned image works fine — it is just placed as a picture rather than as text. One more limit worth knowing: the result is a re-saved file, so a digital signature on the base document does not survive the export. If the base is signed, expect to sign the overlaid copy again.
All of the work happens in your browser. Both files are read locally, composited locally and saved locally; neither is uploaded, which matters most for the documents people most want stamped: unsigned contracts, internal drafts and anything under review before it goes out.
Try it free — PDF Overlay
Stamp one PDF onto another — every page or a page range — with position presets, PDF-point offsets, opacity, and a live preview. Nothing is uploaded.
Open PDF Overlay