Merge PDF files
into one

Why merge PDF files?

It's rare for an important document to arrive as one tidy file. A loan application is a form, two bank statements, and an ID scan. A project handoff is a brief, a spec, and three appendices. Merging those scattered PDFs into one document makes them easier to send, store, and read in order:

• One attachment instead of five — Email a single file rather than a cluttered batch that's easy to lose track of.
• Upload portals that accept one file — Many job, visa, and tender systems allow exactly one PDF. Merging is the only way to submit everything.
• A guaranteed reading order — Cover letter first, résumé second, references last — the reader sees it the way you intended.
• Tidy archives — Keep a contract and all its amendments as one searchable file instead of a folder of fragments.

Common reasons people combine PDFs

• Job applications — Bundle a cover letter, CV, and portfolio into one professional document.
• Invoices and receipts — Combine a month of receipts into a single expense report for accounting.
• Contracts — Join the agreement, the annexes, and the signed signature page into one file of record.
• School and university — Merge assignment pages, scanned worksheets, or a multi-part thesis submission.
• Scanned documents — Stitch pages scanned one at a time back into a complete document.

How browser-based merging keeps your files private

Most online merge tools — Smallpdf, iLovePDF, Adobe Acrobat online — upload every PDF to their servers, combine them in the cloud, and send the result back. For a contract or a bank statement, that means your private document sits on a third-party server, even if only briefly.

PDFduck works differently. When you drop your files onto this page, your browser reads them directly from your device and assembles the merged PDF locally using JavaScript. Nothing is uploaded anywhere. The combined file is created on your own computer or phone, so only you ever see the contents.

Tips for a clean merged PDF

• Set the order before you merge — Use the up and down arrows so the pages flow logically. The top file becomes the first pages of the result.
• Name files by order first — If you add many at once, naming them 1-intro, 2-body, 3-appendix makes arranging them faster.
• Check page sizes — Mixing A4 and US Letter pages is fine, but the result will contain pages of different sizes; that's expected, not a bug.
• Merge once from originals — Combine the highest-quality source files rather than re-exported copies, so text and images stay crisp.

Need to do the opposite — or something else?

PDFduck has a small family of free, private PDF tools that all run in your browser:

• Split PDF — Pull out a page range or break a PDF into single pages.
• PDF to JPG — Turn PDF pages into image files you can share or post.
• JPG to PDF and PNG to PDF — Build a PDF from your images.
• Word to PDF, Excel to PDF, PowerPoint to PDF — Convert Office documents to PDF.

Everything is free and unlimited. Image and PDF tools run entirely on your device.