PDF Merger

Merge multiple PDF files into one online.

Developer

The PDF Merge tool combines multiple PDF files into a single document — entirely within your browser. Whether you need to join scanned receipts, consolidate report chapters, or assemble a portfolio from separate files, this tool handles it without uploading anything to a server. Select your PDFs, arrange them in the desired order, and download the merged result. Powered by the PDF-lib library running client-side, your documents remain private and never leave your device.

About PDF Merge

Merging PDFs is a common task in offices, schools, and personal workflows. Instead of relying on desktop software or cloud services that may require subscriptions and data uploads, this tool performs the merge directly in your browser using JavaScript and the PDF-lib library. The merged PDF preserves the page content, layout, and formatting of each source file. Simply select your files, confirm the order, and download the combined document.

How to Use PDF Merge

  1. Click Select PDF files and choose two or more PDF documents from your computer.
  2. Review the file list — the merged PDF will follow the order shown.
  3. Click the merge button to combine the files.
  4. Download the resulting single PDF file to your device.

Key Features

  • Merges an unlimited number of PDF files in one operation
  • Preserves original page content, dimensions, and formatting
  • 100% browser-based using PDF-lib — no files are uploaded to a server
  • No software installation, no account, no subscription required
  • Fast processing directly on your device with instant download

When to Use This Tool

  • Combining multiple scanned documents or receipts into one file
  • Joining separate chapters or sections into a complete report
  • Assembling a portfolio, dossier, or application package from individual PDFs
  • Preparing a single file for email attachment instead of sending multiple PDFs
  • Merging signed contracts or forms into one archival document

Technical Details

The tool uses the PDF-lib JavaScript library to read each selected PDF, extract its pages, and assemble them sequentially into a new PDF document. Because the processing happens entirely in the browser via the File API and ArrayBuffer handling, your documents never transit through any network. Very large PDFs or a high number of files may be limited by available browser memory. For complementary file tools, check the File Hash utility to verify document integrity.

Conclusion

This free, browser-based PDF Merge tool makes it easy to combine multiple PDFs into one — privately, quickly, and with no sign-up or software installation. Your files stay on your device from start to finish.

Frequently Asked Questions

Is my PDF sent to a server?
No. Merging is done entirely in your browser using the PDF-lib library. Your files never leave your device.
Is there a file size limit?
There is no hard limit, but very large PDFs may slow down or exceed the browser's available memory. For very big documents, consider splitting the merge into smaller batches.
Will the merged PDF keep the original formatting?
Yes. Each page is copied as-is from the source files, preserving layout, fonts, images, and dimensions. No re-rendering or compression is applied.
Can I reorder the files before merging?
The merged PDF follows the order in which you select the files. To change the order, remove and re-add files in your preferred sequence before merging.