Checksum digit calculation for EAN-13

[Gabriela]

Hi,

Can anybody help me with creating a calculation to generate the checksum digit for EAN-13 barcode? I know how it gets worked out.

The calculation needs to consider the 12 digits in the number as even and odd, where the first digit from left is even.

Then:

1. sum the digits in all odd positions and multipy the result by 3

2. sum the digits in all even positions

3. sum the totals calculated in step 1 and 2

4. The check digit is the number which, when added to the totals calculated in step 4, result in a number evenly divisible by 10.

5. If the sum calculated in 4 is already easily divisible by 10 the check digit is 0

Actually I can probably do all the calculations, I just can't figure out how to determine the odd and even positions. Or do I do this by doing a sum of a series of Left(text,number)?

By the way, I'm doing this for a database that's Filemaker 6.

Thanks for any help to get me going.

Gabriela

[ralph.nusser]

Ready solution example with 3 free fonts for EAN-13:

http://www.filemakerprofis.de/tipp_id_22_kategorie_Barcodes.html

http://www.filemakerprofis.de/tippdownloads/ean13.zip

Happy FileMaking Ralph Nusser

[Lee Smith]

There is a sample file in the [color:blue]Sample File Topics that was donated by [color:blue]cjaeger Here

HTH

Lee

[Gabriela]

Thanks a lot to Ralph and Lee, I get it, all very helpful. Finally understand how to use Mod(number,divisor). Sometimes it just needs a little kick to get the brain going.