Merge PDF Files & Auto-Scale to Any Size
Combine multiple PDFs and automatically resize all pages to A4, A3, A5, or Letter. 100% free, no uploads — everything happens in your browser.
Drop PDF files here
or click to browse from your device
Your files stay private — all processing happens in your browser
Auto-Scale Pages to Standard Sizes
Unlike other PDF mergers, AltaPDF lets you automatically resize all pages to a standard paper size after merging. Perfect when combining documents from different sources for consistent printing.
- A4 — 210 × 297mm
- A3 — 297 × 420mm
- A5 — 148 × 210mm
- Letter — 8.5 × 11in
Sizes
All pages scaled proportionally
How It Works
Merge and scale your PDFs in three simple steps
Upload PDFs
Drag and drop or browse to select multiple PDF files from your device.
Arrange & Scale
Reorder files as needed and select your target page size.
Download
Click merge and your combined PDF downloads instantly.
Why Choose AltaPDF?
The most feature-rich free PDF merger online
100% Private & Secure
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
No waiting for uploads. Merge happens instantly on your device.
Auto Page Scaling
Automatically resize all pages to A4, A3, A5, or Letter.
Completely Free
No hidden fees, no premium plans, no watermarks.
Works Everywhere
Desktop, tablet, or mobile. Any modern browser.
Unlimited Usage
No file size limits, no daily caps.
Frequently Asked Questions
Everything you need to know about AltaPDF
Yes, completely free. No hidden fees, no premium plans, no watermarks, no limits.
Ready to Merge Your PDFs?
Combine and scale your PDF files in seconds. Free, fast, and private.