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How-To Guide

How to Merge Multiple PDFs Into One

Combining multiple PDFs into a single file is a routine task — assembling a contract from signed pages, building a portfolio from individual documents, or merging scanned chapters into a complete book. Modern PDF tools handle merging without re-encoding, so quality is preserved exactly.

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Step-by-step instructions

  1. 1

    Upload all PDF files in order

    Select all .pdf files you want to combine. Drag-and-drop interfaces let you reorder pages before merging — verify that the sequence is correct.

    Go to converter
  2. 2

    Choose merge order and settings

    Confirm the order. Some tools let you insert pages from individual PDFs at specific positions, or interleave odd/even pages for two-sided scanning workflows.

  3. 3

    Download the merged PDF

    The output is a single PDF with all source documents concatenated. Bookmarks and metadata from the first file are typically preserved; from subsequent files they may be discarded.

Why convert PDF to PDF?

Merging PDFs is a one-of-a-kind operation that's universal in business — every contract, every report, every scanned book has been merged at some point. Doing it well preserves every byte of the originals.

Your files never leave your device

FormatDrop runs the conversion engine entirely inside your browser using WebAssembly. No file upload. No server. Nothing stored. You can verify this by opening DevTools → Network tab and watching: zero upload requests.

Frequently asked questions

Best command-line tool to merge PDFs?
qpdf: `qpdf --empty --pages a.pdf b.pdf c.pdf -- output.pdf`. PDFtk: `pdftk a.pdf b.pdf c.pdf cat output output.pdf`. Both preserve the original PDFs exactly without re-encoding.
How do I merge PDFs on a Mac?
macOS Preview: open the first PDF, drag additional PDFs into the sidebar, save as new PDF. Or use the command line: `"/System/Library/Automator/Combine PDF Pages.action/Contents/MacOS/join" -o output.pdf input1.pdf input2.pdf`.
Can I merge PDFs in Python?
Use PyPDF2: `from PyPDF2 import PdfMerger; merger = PdfMerger(); for f in ['a.pdf', 'b.pdf']: merger.append(f); merger.write('output.pdf')`. Or pypdf (the maintained fork).
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