About AltaPDF
AltaPDF is a free online tool for merging PDF files with a unique auto-scaling feature. We built this to provide a simple, private way to combine PDF documents without compromising your data.
What Makes Us Different
Unlike other PDF mergers, AltaPDF offers automatic page scaling — resize all pages to A4, A3, A5, or Letter size after merging. Perfect for creating print-ready documents from mixed sources.
Our Mission
Basic document tools should be free and accessible to everyone. Many online PDF tools require uploading files to remote servers, raising privacy concerns. AltaPDF is different — everything happens in your browser.
Privacy First
All PDF processing happens directly in your web browser using JavaScript. Your files never leave your device. We don't upload, store, or have access to any of your documents.
Key Features
- Auto page scaling — Resize to A4, A3, A5, or Letter
- 100% private — Files never leave your device
- No registration — Start using immediately
- No watermarks — Clean, professional output
- Unlimited usage — No file size or daily limits
Technology
AltaPDF is built with modern web technologies including Next.js and pdf-lib, an open-source library for PDF manipulation. This allows us to process PDFs entirely client-side without any server involvement.