Got a simplex (single-sided) scanner and duplex (double-sided) documents? Simplex Repaginator converts simplex-scanned PDFs into properly duplex-paginated PDFs. Simplex Repaginator is open-source software and provided absolutely free of charge.

Properly Paginated PDFs with a Simplex Scanner

So, long story short, I have a simplex (single-sided) document-fed scanner and lots of duplex (double-sided) documents that I’m trying to archive. Rather than mess around manually correcting page orderings, I wrote a small Java application to do it for me. It’s pretty simple.

First, scan your entire document face-up. Second, as part of the same scan batch scan the entire document face-down. Third, run it through the Simplex Repaginator. Fourth, party time!

Repagination Algorithm

The Simplex Repaginator expects the pages of your input document to be ordered such that, if you grabbed the next page of the output document alternating between the front and back of the input document, you would end up with something properly paginated. So, if you had a four-page input document scanned according to the directions above you’d start with a PDF whose logical page order was 1,3,4,2. By alternating between grabbing the front and back pages of the input document, Simplex Repaginator re-orders your PDF to 1,2,3,4.


Sometimes you’ll repaginate a document that isn’t in the expected input pagination order. Perhaps it was already properly paginated! When this happens, just click the “unrepaginate” button. The Simplex Repaginator algorithm runs in reverse, taking your 1,4,2,3 input document (the result of repaginating a properly paginated 4-page document) and producing the original 1,2,3,4 output document.

Absolutely Free Of Charge

Simplex Repaginator is free software, and will always be free software. There is no registration and no shady installation either, so you won’t wind up with junk (like search toolbars) you don’t want. There are no advertisements, either on this site or in the software. I’m doing this because it’s a hobby and it’s fun, not to make money.

Open Source & Open Source Powered

Simplex Repaginator is released under the Apache 2.0 License. It is made at all possible by the very excellent Apache PDFBox library from the Apache Software Foundation. Kudos to the PDFBox developers!

Latest News From the Blog

Stable 0.0.6

Released stable 0.0.6. GUI improvements.

Stable 0.0.5

Just posted stable release 0.0.5.

Stable 0.0.4

Stable 0.0.4 released.  Mostly eye candy, but some bug fixes too.