ConvertDuck

Merge PDFs

Upload multiple PDF files and combine them into a single PDF.

Select multiple PDF files or drag & drop them here.

No PDF files selected.

The Safest Way to Organize Your PDFs

Managing scattered documents can be chaotic. This tool allows you to join multiple PDF files into a single, organized document instantly. Unlike other services that require uploading your sensitive data to a cloud server, our local processing technology merges your files right on your device. This guarantees that your contracts, medical records, or legal documents never leave your computer.

How to Combine PDFs

1. Select Your Files

Drag and drop the PDF documents you want to combine. You can select bulk files at once.

Hold Ctrl/Cmd to select multiple files from your folder.

2. Reorder Pages

Arrangement matters. Drag files up or down to set the correct order, or use the 'Sort by Name' button for automatic organization.

The top file will be the first page of your new document.

3. Merge & Save

Click 'Merge & Download' to process. The browser creates your new file instantly without waiting for network uploads.

Why Professionals Use This Tool

  • ✓ Zero Data Leaks

    Since we use WebAssembly technology to process files locally, your confidential documents are never exposed to the internet or third-party servers.

  • ✓ Drag & Drop Sorting

    Easily rearrange your file sequence visually. No need to rename files just to get them in the right order.

  • ✓ Preserves Quality

    The merger copies pages exactly as they are, maintaining the original resolution, text clarity, and formatting of your source documents.

System Requirements

Supported Format PDF (Portable Document Format) v1.4 and higher
Browser Chrome, Edge, Firefox, Safari (Latest versions recommended)
Processing Limit Dependent on device RAM (typically handles 100+ pages easily)

Local Merging vs. Server Uploads

Feature Our Local Tool Cloud-Based Tools
Privacy 100% Private (No Upload) Files stored on servers
Speed Instant (No Upload Time) Slow (Upload + Download)
File Count Unlimited Often capped (e.g., max 20 files)

Common Questions

Q. Is it safe to merge confidential legal documents? ▼
Yes. Because the code runs entirely in your browser, the files never leave your specific device. It's as safe as working offline.
Q. Can I merge password-protected PDFs? ▼
Currently, you must remove the password protection before uploading. The browser cannot decrypt locked files automatically.
Q. Does this affect the quality of my images? ▼
No. The tool performs a 'page copy' operation, meaning it takes the exact data from the original pages and stitches them together without re-compressing.
Q. Why did the merge fail? ▼
This usually happens if a file is corrupted or if the total size exceeds your browser's memory limit (typically around 500MB-1GB on modern computers).