The Upc/Ean Checksum Character - Worth Data 7100 RF Terminal Series Owner's Manual

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 meth-
ods 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:
odd
Starting with the leading digit, 8, take the sum of all the characters in the odd positions.
Multiply the result of step 1 by 3.
Now take the sum of all the even-position characters.
Add the result in Step 2 to the result in Step 3.
Subtract the result from the next higher multiple of 10.
This same formula is used for EAN-13 (using the 1-12 digits) and EAN-8 (using the 1-7 digits).
UPC-E Checksum Calculation
Use the sample data of 123456 to demonstrate the UPC-E checksum calculation:
The 6 digit UPC-E code is converted to a 10-digit code, using an expansion scheme based on the sixth digit:
Because the sample UPC-E code ends in a 6, the insertion digits 0000 are inserted at the sixth digit (insertion position 6):
Add the Number System Character of 0 to the sample data:
Use the UPC-A check digit calculation described in the previous section to produce a check digit as if it were a UPC-
A code. The check digit for the sample data is:
The complete 8 digit code consists of the Number System Character, the original 6 digit code and the check digit:
8
8 + 9 +8 + 4 + 3 + 1 = 33
3 + 9 + 5 + 1 + 8 = 26
Next higher multiple of 10 over 125 = 130
5 is the Modulo-10 check character. The data to be printed becomes:
If the code UPC-E Data
ends in:
0 abcde0
1 abcde1
2 abcde2
3 abcde3
4 abcde4
5 abcde5
6 abcde6
7 abcde7
8 abcde8
9 abcde9
3 9 9 8 5
even odd even odd even
33 x 3 = 99
99 + 26 = 125
130 - 125 = 5
183145899385.
Insertion Digits Insertion
Position
00000 3
10000 3
20000 3
00000 4
00000 5
0000 6
0000 6
0000 6
0000 6
0000 6
1234500006
01234500006
5
01234565
87
4 1 3 8 1
odd even odd even odd
10 digit code
ab00000cde
ab10000cde
ab20000cde
abc00000de
abcd00000e
abcde00005
abcde00006
abcde00007
abcde00008
abcde00009