Advanced · Use case

Combine Front and Back Scans Into One PDF

Your scanner doesn't support automatic duplex scanning. So you scanned all the front sides first, then flipped the stack and scanned all the back sides. Now you have two PDFs that need to be interleaved — front 1, back 1, front 2, back 2. OneClickPDF's interleave tool does this in seconds.

Updated 24 February 20261 min read4 steps

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The Problem

You scanned a double-sided document as two separate jobs: one for fronts, one for backs. The two PDFs need to be merged in alternating order. Manually reorganizing pages would take forever on a long document. And the backs might be in reverse order since the bottom of the stack was scanned first.

How It Works

  1. Open Interleave Pages

    Go to OneClickPDF's Interleave Pages tool.

  2. Upload both scan files

    Upload the fronts PDF as the first file and the backs PDF as the second file.

  3. Enable reverse for backs

    If you flipped the stack to scan backs, the back pages are in reverse order. Enable 'Reverse second file' to fix this automatically.

  4. Interleave and download

    Click Interleave. The tool creates a properly ordered document: front 1, back 1, front 2, back 2, etc. Download the complete document.

Frequently Asked Questions

How do I know if I need to reverse the backs?
If you placed the stack face-down for the back scan (most common), the last page was scanned first — so the backs are in reverse order. Enable reverse to fix this. If unsure, try both ways and check the first few pages.
What if fronts and backs have different page counts?
If one file has more pages, the extras are appended at the end. This handles cases where the last sheet is single-sided.
Can I preview the result before downloading?
The tool shows the resulting page order so you can verify the interleaving is correct before downloading.

The classic double-sided scanning problem solved in 10 seconds. No more manual page-by-page reordering — just upload both stacks, toggle reverse if needed, and download the correctly interleaved document.

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Related Guides

Open Interleave Pages