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Alternate & Mix

Interleave the pages of two PDFs

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About Alternate & Mix

If your scanner produced one file with the front pages and another with the backs, drop both in and the tool will interleave them 1, 1, 2, 2, 3, 3. If the second file was scanned in reverse, tick the reverse option.

How to combine two one-sided scans into one document — step by step

  1. Upload the file with the odd pages — the fronts of your sheets.
  2. Upload the file with the even pages — the backs.
  3. Tick the reverse option if the second file came out in reverse order, which is what most scanners produce.
  4. Download the correctly interleaved document.

The double-sided scanning problem

A scanner without a duplex feeder makes you scan one side of the stack, then flip it and scan the other. You end up with two files: pages 1, 3, 5, 7 in one and pages 2, 4, 6, 8 in the other — and because you flipped the stack, the second file is usually in reverse order, 8, 6, 4, 2.

This tool weaves them back together in the right sequence. Tick the reverse box for the second file and the result reads 1, 2, 3, 4 as it should.

Checking the result

Always open the merged file and look at the first four pages before you send it anywhere. If page 2 is the back of a different sheet, you needed the reverse option — or you needed it off. It takes ten seconds to check and saves resending a document to an office.

Frequently asked questions

What if the two files have different page counts?

No problem — the leftover pages are added at the end.

How do I handle a duplex scan?

Tick the 'reverse the second file' option for the backs.

Is my file uploaded?

No. It is interleaved in your browser.

What if the two files have different page counts?

The extra pages are added at the end. That normally means a sheet was missed on one pass.

Why is my second scan in reverse?

Because flipping the stack reverses the order. That is normal, and the reverse option is there for it.

Can I use it to alternate any two documents?

Yes — it simply takes one page from each file in turn.

🔒 Everything on this page happens inside your browser. Your file is never uploaded to a server.

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