What Is a PDF Merger?
A PDF merger is a tool that combines two or more separate PDF documents into a single file, preserving the original page order — or a custom order you define. This is one of the most common document management tasks, used to consolidate scanned pages, combine chapters of a report, assemble multi-part contracts, or compile invoices into one file for easier sharing and archiving.
Browser-based PDF mergers like this one run entirely on your device using JavaScript libraries such as pdf-lib, meaning your documents are never uploaded to a remote server. This makes them ideal for merging confidential business documents, legal contracts, financial records, or personal files without privacy concerns.
How to Merge PDF Files
Upload your PDF files
Drag and drop multiple PDFs into the drop zone, or click to browse and select files. You can add more files at any time before merging.
Reorder your files
Drag files using the grip handle, or use the up/down arrows to set the exact order pages will appear in the final document.
Select pages (optional)
Click the preview icon on any file to expand its page thumbnails. Uncheck any pages you don't want included in the merged PDF.
Rotate pages (optional)
Use the rotate button on individual pages, or rotate an entire file's pages at once, to fix sideways or upside-down scans.
Merge and download
Name your output file and click Merge & Download. The combined PDF is generated instantly in your browser and downloads automatically.
Common Use Cases
Combining Scanned Pages
Merge individually scanned pages into one complete document.
Assembling Reports
Combine cover pages, chapters, and appendices into a single report.
Compiling Invoices
Bundle multiple invoices or receipts into one file for accounting.
Merging Contract Pages
Combine signature pages, amendments, and exhibits into one contract.
Academic Submissions
Merge a thesis, cover page, and appendices for a single submission.
eBook Compilation
Combine multiple chapter PDFs into a single book-length document.
Frequently Asked Questions
Technical note: This tool uses the open-source pdf-lib JavaScript library to copy page content streams directly from source documents into a new PDF, preserving original fonts, images, and vector graphics without re-rendering. Encrypted or password-protected PDFs cannot be processed without first removing the password, as browser-based libraries cannot decrypt protected content without explicit credentials.
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