The upc/ean checksum character, Checksum calculation for upc-a, ean-13 and ean-8 – Worth Data 5000 User Manual
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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). 
 
