UPC Check digit calculator

[Code Flunkie]

Hi,

a while back I had some help on this forum with a macro to check the check digit of a barcode. The macro works perfectly except for the fact that I realized my formula is wrong for the 13 digit barcode. I realized that if the barcode has an even number of characters then the odd digits are summed and multiplied by 3 and the even numbers are just summed. if the barcode has an odd number of characters then the even digits should be summed and multiplied by 3 and the odd numbers should be summed. Unfortunately I don't know how to correct the macro for this, so any help would be much appreciated.

Thanks,

Chris

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[Leith Ross]

Hello Code Flunkie,

Perhaps this macro will help you. It returns checksums for both UPC-A and EAN-13 codes.

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[caryfloric]

Hi,

a while back I had some help on this forum with a macro to check the check digit of a barcode. The macro works perfectly except for the fact that I realized my formula is wrong for the 13 digit barcode. I realized that if the UPC-A barcode has an even number of characters then the odd digits are summed and multiplied by 3 and the even numbers are just summed. if the barcode has an odd number of characters then the even digits should be summed and multiplied by 3 and the odd numbers should be summed. Unfortunately I don't know how to correct the macro for this, so any help would be much appreciated.

Thanks,

Chris

The checksum of UPC-A and EAN-13 barcode is based on a modulo 10 calculation and there are detailed steps at http://www.barcodeisland.com/ean13.phtml.

[Leith Ross]

Hello caryfloric,

You do realize that this post is more than a year old. I appreciate your additional information to this post.