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Merge PDFs

Combine multiple PDF files into one document — invoices, contracts, scanned reports, or transcripts. Free browser-based merger that runs locally, ensuring complete privacy.

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Select PDF files

You can select multiple files at once

Max file size: 100MB • Multiple files allowed

or drag and drop · press Enter to browse

How to Use

  1. Upload two or more PDFs to merge — invoices, scanned contracts, expense reports, university transcripts, or RFP bid packets all work.
  2. Reorder files with the ↑↓ buttons or drag them into the right sequence (expense claims: by date; contracts: cover → clauses → annexes).
  3. Click 'Merge PDFs' — pdf-lib processes everything in your browser, so confidential documents never reach a server.
  4. The merged PDF downloads automatically with the original layout, text, and images intact.
  5. Useful for monthly invoice bundles to your accountant, CV + reference letters for a job application, or compiling multi-page scan jobs.
  6. All merges are performed locally without file uploads, keeping your financial, medical, and personal documents completely private.

All processing is done in your browser, and files are never sent to a server.

Frequently Asked Questions

There is no strict limit on the count. However, since all merging runs locally in your browser's memory, merging dozens of extremely large scanned documents (e.g., hundreds of megabytes) might be constrained by your device's available RAM.
Yes. The merge process combines pages at the PDF structure level without re-encoding or compressing images, preserving the original quality, vector paths, embedded fonts, and layout.
Yes, you can easily reorder files using the up and down arrow buttons or drag-and-drop before executing the merge.
No. The merging is executed entirely client-side using pdf-lib.js in your browser's sandbox. Your documents never leave your device, ensuring total security for confidential contracts or financial invoices.
Yes. Internal hyperlinks and external URLs are fully preserved. However, bookmarks (outlines) from individual files may need to be rebuilt or consolidated depending on how the browser's PDF viewer handles them.
No. Encrypted or password-protected PDF files must be decrypted (unlocked) first before you can merge them. You can use our PDF Unlock tool to remove the password beforehand.
Scanned document merges can result in large files. After merging, you can run the output file through our PDF Compress tool, which typically reduces file size by 30% to 70% while keeping it under email limits (e.g., 25MB for Gmail).
The tool is completely free with no usage limits. However, since processing occurs in your browser's memory, we recommend keeping file sizes under 50MB (especially for heavy files like PDFs or videos) to ensure stability.
No. All tools on ConvertBox are 100% free. We do not insert watermarks, limit features, or require any registration or payment.
Yes. Once the page and its local library dependencies are loaded in your browser, the conversion logic runs completely offline without needing an active internet connection.

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