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Merge PDF Files

Merge PDF files for free in the order you choose. Rearrange individual pages afterwards in Organize. Local browser processing, no signup or watermarks.

  • Combine multiple PDF files into one document
  • Set the file order before merging; organize individual pages afterwards
  • PDF processing runs locally in your browser

Merging PDFs combines files in the order you set in the queue, keeping the page order within each file. Use Open in Organize on the completed result to rearrange individual pages. OpenPDF runs the merge locally with pdf-lib; capacity depends on the PDFs and browser/device resources, so review the result before sharing.

How it works

  1. Add your PDFs. Drag and drop multiple PDF files onto OpenPDF or click to browse.
  2. Set the file order. Drag the file rows or use their move buttons. Pages within each file keep their original order.
  3. Merge locally. OpenPDF combines the files 100% in your browser using pdf-lib — nothing uploads.
  4. Review and save. Click Download to save the combined file, or choose Open in Organize to rearrange individual pages before saving.

Common use cases

  • Combining a scanned cover letter, CV and references into one PDF for a job application.
  • Merging supplier invoices into a monthly bundle for bookkeeping.
  • Assembling a client-facing proposal from chapters exported from different design tools.
  • Stitching together bank statements spread across quarterly PDFs for a loan application.

Try a merge you can check

Use these small PDFs created for this example, with no personal data. File A has two portrait pages labelled A1 and A2; file B has one landscape page labelled B1.

  1. Download both samples and add them to the merge queue above.
  2. Put file A first and file B second. The queue should contain 2 files and 3 pages.
  3. Select Merge, then Download. Open the saved result and read its page labels.

Expected result: 3 pages in order A1 → A2 → B1. The first two remain portrait (300 × 400 PDF points); the last remains landscape (400 × 300 points).

Repeat with B before A: expect B1 → A1 → A2. To change individual page positions afterwards, use Open in Organize on the completed result.

This sample checks order, page count and dimensions. It does not prove preservation of every form, bookmark, signature or accessibility tag in other documents. Review your actual output before sharing it.

Frequently asked questions

Is there a limit on how many PDFs I can merge?

Capacity depends on the browser/device resources and the PDFs being combined. Large batches may take longer or fail locally; review the operation's message if it reaches a limit.

Does merging preserve bookmarks and annotations?

OpenPDF preserves the content of each page, including annotations embedded in the source files. Bookmark structures may not survive in all cases depending on how the source PDF was generated.

Can I change the order of files and pages?

Before merging, drag the file rows or use their move buttons to set the file order. Pages within each file keep their original order. To rearrange individual pages after merging, choose Open in Organize on the completed result.

Is merging uploaded to a server?

No. pdf-lib combines the files in your browser. Nothing ever touches a server.

Why OpenPDF

OpenPDF is an independent project where PDF document processing runs in the browser using WebAssembly and modern JavaScript APIs. The toolkit includes merge, split, sign, organize, annotate, compress, watermark, page numbers, add image and fill forms. Practical limits depend on the operation, document and device. The page source and privacy policy describe consent controls, analytics, advertising and optional services before you use the tool with sensitive documents.

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