Overlay PDF

The stamp is never scaled to fit; it keeps the natural size of the stamp page you selected. When both files share dimensions that is exactly what you want, and a letterhead lines up edge to edge. When they differ, the stamp is placed at the anchor you chose and simply keeps its own size, so one larger than the base extends past the visible area and gets clipped, while a smaller one leaves the base showing around it. The five position chips and the live preview — which outlines the stamp's bounds in brand red even at low opacity — let you see this before you save. If the sizes need to agree, run the stamp file through Resize PDF first, or re-export it at the target dimensions from whatever produced it.

The stamp is always drawn over the base page's existing content, never behind it. It is written after that content, so it sits on top, and there is no send-to-back option anywhere in the tool. For letterhead or a background texture that ought to appear behind the text, the practical answer is the opacity slider: at the default 60 per cent the base content reads clearly through the stamp, and it goes down to 10 per cent if you need it fainter. If a true background is essential and the job is a single page, you can reverse the roles and make the letterhead the base with the document page as the stamp. Note too that if the stamp page paints its own white background — many do — that fill covers what lies beneath it, which is precisely what the opacity control is for.

Overlay PDF never rasterises the stamp, so no quality is lost in the overlay itself. The chosen stamp page is embedded as a reusable page object and drawn by reference, so vector text stays vector text, thin rules stay thin, and a stamp applied to two hundred base pages is stored once rather than two hundred times. Text inside the stamp remains real text in the output, meaning a letterhead's address block is still selectable and searchable afterwards. Only what a reader would actually see is embedded — the visible box left after any crop — and the stamp page's own rotation flag is carried through, so a landscape stamp is not tipped onto its side. If the stamp file is itself a scan, it stays exactly as sharp or as soft as it already was, because nothing is re-encoded.

The Apply to control decides which base pages get stamped, and it has three settings. Every page stamps the whole document; First page only stamps page one, the usual choice for letterhead belonging on a cover; and Page range opens a text box taking a comma-separated mix of single pages and hyphenated spans, such as 1-3, 5, 8-10. Spaces are ignored, a reversed span like 9-6 is read the right way round, and numbers beyond the end of the document are dropped rather than raising an error. A counter under the box shows how many of the document's pages your expression currently selects, and the preview says plainly when the page you are looking at falls outside the scope — so nothing is stamped by surprise. The status line confirms the final count after saving.

Both files stay on your machine from start to finish. The base document and the stamp are read from disk by the browser, the stamp page is rendered locally to build the live preview, the composition happens in the tab, and the combined result is written to your downloads with an -overlaid suffix. Neither file is uploaded and neither is retained. That matters more than usual for this tool, because the two files are often sensitive in different ways — a signature page and the contract it belongs to, or your own letterhead and a client's draft agreement. Nothing about either one travels anywhere, and once the page has loaded the tool carries on working with the network switched off.

Overlay PDF is free, with no account, no watermark on the result and no cap on the number of base pages. Both documents are held in memory while the overlay is composed, so device memory is the real limit rather than any policy: the status line updates page by page as it works, and a very long base document on a phone will be noticeably slower than the same job on a laptop. Encrypted files are the one firm stop — a password-protected PDF must be unlocked with Remove PDF password before it can be used in either slot. The saved file carries only your two documents combined, with nothing added on the page or in the metadata.