Why Merge PDF Files?

Combining multiple PDFs into a single document is one of the most common document tasks. Whether you're:

• Assembling a report from multiple sections
• Combining scanned pages into one file
• Merging invoices for record-keeping
• Creating a portfolio from separate documents

How to Merge PDFs Online for Free

Step 1: Open the Merger

Go to sempdf.com/merge-pdf.

Step 2: Add Your Files

Drag and drop multiple PDF files into the upload area. You can add 2 or more files. The order they appear is the order they'll be merged.

Step 3: Reorder (Optional)

Drag files to rearrange them in your preferred order.

Step 4: Click Merge

Hit "Merge PDFs" and download your combined document.

How It Works Behind the Scenes

Our merger uses pdf-lib to read each PDF's pages and copy them into a new document. This means:

• Original quality is preserved — no re-rendering or compression
• Bookmarks and links are maintained
• Page sizes can be mixed (A4 + Letter + custom)
• The process is fast because it's a simple page copy, not a re-encode

Tips for Merging PDFs

• File order matters — arrange files before merging
• Large files may take a moment — Pro users can merge files up to 100 MB each
• Password-protected PDFs need to be unlocked first
• Batch merging — free users can merge up to 5 files, Pro users up to 50

Security & Privacy

Your files are processed securely with 256-bit encryption and deleted immediately after merging. We never store your documents.