The upc/ean checksum character, Checksum calculation for upc-a, ean-13 and ean-8 – Worth Data 5000 User Manual
Page 118
117
option of transmitting in the ISBN format.
ISBN 0-553-37062
ISBN specifications are available from:
American National Standards Institute
Customer Service
11 West 42
nd
St.
New York, NY 10036
document ISO 2108:1992
The UPC/EAN checksum character
The last character in a UPC-A, UPC-E, UPC-E1, EAN-13 or EAN-8 bar code is the checksum. For reference, these are the methods
of calculation:
Checksum calculation for UPC-A, EAN-13 and EAN-8
Use Worth Data‟s phone number (it's not a real UPC-A code) as sample data:
18314589938
Assign even and odd positions, starting at the right and moving left:
8
3
9
9
8
5
4
1
3
8
1
odd even odd even odd even odd even odd even odd
Starting with the leading digit, 8, take the sum of all the characters in the odd positions.
8 + 9 +8 + 4 + 3 + 1 = 33
Multiply the result of step 1 by 3.
33 x 3 = 99
Now take the sum of all the even-position characters.
3 + 9 + 5 + 1 + 8 = 26
Add the result in Step 2 to the result in Step 3.
99 + 26 = 125
Subtract the result from the next higher multiple of 10.
Next higher multiple of 10 over 125 = 130
130 - 125 = 5
5 is the Modulo-10 check character. The data to be printed becomes:
183145899385
This same formula is used for EAN-13 (using the 1-12 digits) and EAN-8 (using the 1-7 digits).