Merge PDF
Merge multiple PDF files into one online for free. Reorder pages, combine PDFs, and download instantly. No upload, 100% private.
About This Tool
PDF Merger combines multiple PDF files into a single document. Drag and drop to reorder pages, select specific page ranges from each file, and merge them instantly — perfect for assembling reports, combining invoices, or packaging multiple documents into one cohesive file.
Drag & drop PDF files here, or click to browse
Only PDF files are supported
How to Use
- Drag and drop PDF files into the upload area above, or click to browse and select files.
- Use the up/down buttons to reorder files as needed.
- Click the 'Merge PDFs' button to combine all files into one.
- The merged PDF will download automatically when complete.
Frequently Asked Questions
Is it safe to merge PDFs here?
Yes, all processing happens entirely in your browser. Your files are never uploaded to any server, making it 100% private and secure.
How many PDFs can I merge?
There is no hard limit. It depends on your browser's available memory. Typically, you can merge dozens of PDFs without any issues.
Is the merged PDF quality preserved?
Yes, all content, formatting, images, and links from the original PDFs are preserved exactly. There is no compression or quality loss.
Can I change the page order?
Yes, use the up/down buttons in the file list to reorder files before merging. The merge follows the list order from top to bottom.
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How It Works
Each uploaded PDF is read as an ArrayBuffer using the File API and loaded with pdf-lib. The tool creates a new blank PDF document and iterates through your files in the specified order. For each source PDF, the selected pages are copied into the new document using pdf-lib's copyPages() method, which preserves original formatting, fonts, images, and annotations. Page dimensions and rotations are maintained exactly as in the originals. The merged PDF is generated via save() and made available for download as a Blob.
The entire merging process runs client-side using the pdf-lib library and the File API. Your PDF files are never uploaded to a server — everything stays in your browser for complete privacy.