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Merge PDF files

Combine several PDFs into one file free — no page limit, no watermark, no signup. Text stays selectable, and nothing is ever uploaded.

Drop files here (up to 40)

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Results appear here. Nothing is uploaded.

    How it works

    Each document is parsed with @cantoo/pdf-lib, and pages are transferred into a new document with copyPages, which re-embeds the existing content streams, fonts and images rather than redrawing them. Nothing is rasterised, so text stays selectable and searchable, embedded fonts survive, and the output lands close to the combined size of the inputs. Files are appended in the order you select them. This tool downloads no wasm module at all.

    What to watch out for

    Password-protected files are refused, not silently skipped

    An encrypted PDF cannot be read without its password. The tool detects this and names the file rather than producing a merged document that is quietly missing pages. Remove the password in your PDF reader first.

    Form fields can collide

    If two documents contain interactive form fields with the same internal name, only one set of values survives the merge. Flatten the forms before merging when the filled-in values matter.

    Digital signatures stop being valid

    A signature certifies the exact bytes of the document it was applied to. Producing a new merged file necessarily invalidates it, which is a property of how signing works rather than a limitation here.

    Limits

    Files up to about 200 MB work reliably. Beyond that, the ceiling is your device's memory rather than any rule we impose — the work happens on your own machine. Tested in Chrome 140, Firefox 143, Safari 18.

    Why merging locally is different

    Every mainstream free merge tool works the same way: you upload your documents, a server combines them, you download the result. That design has three costs that have nothing to do with the merge itself.

    The first is privacy. The documents people merge are rarely trivial — scanned contracts, invoices for an accountant, a mortgage application assembled from six separate letters. A server-side tool receives complete copies.

    The second is waiting. Two transfers of a 60 MB document over a domestic upload connection takes far longer than the merge does, and neither transfer accomplishes anything.

    The third is the caps. Free tiers exist to keep bandwidth bills down, which is why they limit file size and how many documents you may combine at once. Here the merge happens on your own processor, so the constraint is your device’s memory rather than someone else’s budget.

    What “text stays selectable” actually means

    This distinction separates a real merge from a lazy one, and it is worth understanding because it is easy to get wrong invisibly.

    A PDF page is a set of drawing instructions: place this glyph from this font at these coordinates. A correct merge copies those instructions into the new document. A shortcut implementation renders each page to a bitmap and puts the picture on a fresh page — the result looks identical on screen and is completely broken in every other respect. You can no longer select or copy text, search finds nothing, screen readers get an empty page, and the file balloons because photographs of text compress badly.

    This tool copies page objects. A test in the build asserts that merged output contains font resources and no embedded page images, so this cannot regress silently.

    Order and page count

    Documents are combined in the order you add them. Every file’s pages are appended whole; there is no need to specify ranges. The result reports the total page count so you can confirm at a glance that nothing was dropped — useful when merging a dozen files where a missing page would otherwise be easy to overlook.

    Your files never leave your browser. Last updated 2026-07-31.