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Merge PDF

Combine multiple PDFs into one file, right in your browser. Reorder before merging; nothing is uploaded.

Runs in your browser — files never leave your device

How it works

Add two or more PDFs, put them in order, and click merge: the tool builds a brand-new PDF right in your browser with the open-source pdf-lib library. Every page of every file is copied, in your chosen order, into the new document, which downloads as merged.pdf. Combine a 12-page contract with a 3-page annex and you get a single 15-page file, contract first if it sits first in the list.

The key detail is that pages are copied, not re-rendered. Nothing is converted to images or recompressed: text stays selectable and searchable, vector graphics stay crisp at any zoom, and the fonts and images each page depends on travel with it. Mixed inputs are fine too — an A4 page, a US Letter page, and a landscape page each keep their own size and orientation in the merged file.

The list is the contract: the file at the top becomes the first pages of the output, and the up/down arrows and remove buttons let you rearrange or drop files before committing. The merge button activates once at least two files are loaded. Since whole files are combined, the output size is roughly the sum of the inputs.

Two honest limitations. Password-protected PDFs cannot be opened for copying, so they stop the merge with an error — remove the password first. And because merging copies pages into a fresh document, document-level extras such as bookmark outlines, fillable form fields, and the sources’ title metadata may not carry over; the pages themselves, including their layout and graphics, always do.

Everything happens on your device. The files are read into your browser’s memory, combined there, and downloaded from there — no upload, no server-side queue, no copy of your documents left behind. For confidential paperwork, that is the whole point.

Frequently asked questions

Does merging reduce the quality of my PDFs?
No. Pages are copied as PDF objects, not re-rendered into images, so text remains selectable and searchable, vector graphics stay sharp at any zoom, and embedded images are not recompressed. The pages in the merged file are the same pages that were in the sources.
Can I control the order of the files?
Yes — use the up/down arrows to arrange the list before merging; the file at the top comes first. Within each file, pages keep their original order. The tool merges whole files, so if you only need some pages from a document, extract them first.
Can I merge password-protected PDFs?
No. Encrypted files cannot be opened for page copying, so the merge stops with an error. Remove the password first — for example by opening the file with its password and re-saving an unprotected copy — then merge.
Are bookmarks, form fields, and attachments carried over?
Page content and layout carry over completely, but the merge builds a brand-new document from copied pages, so document-level features — bookmark outlines, fillable form fields, file attachments, and the original title and author metadata — may not survive. Treat the output as a clean page-for-page combination.
Is there a limit on file count or size?
No fixed limit — the practical ceiling is your device’s memory, since every file is read and rebuilt in the browser. Dozens of normal documents merge in seconds; a stack of very large scanned PDFs adding up to hundreds of megabytes may be slow or fail on low-memory devices. Expect the output to be roughly the combined size of the inputs.
Can I mix different page sizes and orientations?
Yes. Each page keeps its own dimensions and rotation, so an A4 report, a Letter contract, and a landscape spreadsheet export can live in one file. No page is cropped or scaled to match the others.
Are my PDFs uploaded to a server?
No. The merge runs entirely in your browser using the open-source pdf-lib library — the files are read into memory on your device, combined there, and downloaded from there. Nothing is transmitted, which makes the tool appropriate for contracts, bank statements, medical records, and other documents you would not upload to a stranger’s server.

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