Sample Check Digit

Sample Checkdigit Calculation:
Checkdigits are used to verify accuracy of data scanned from the OCR line. By performing a mathematical calculation on all the numbers in a scanline, an additional digit (the checkdigit) is generated and printed with the scanline. The same calculation is performed when the line is read to ensure that the checkdigit is the same. Although checkdigit routines vary widely from application to application, the following is an example of a typical Mod 10 checkdigit calculation.

The following is the sample scanline (see Scanline Recommendations).

003456789011102960000000000100000000010008

The checkdigit in this example will be calculated as follows:

1. Multiply each digit position by the weight (2121212121) to obtain the products:

003456789011102960000000000100000000010008

XXXXXXXXXXX

21212121212 etc.

0 X 2 = 0

0 X 1 = 0

3 X 2 = 6

4 X 1 = 4

5 X 2 = 10

6 X 1 = 6

7 X 2 = 14

8 X 1 = 8

9 X 2 = 18

0 X 1 = 0

1 X 2 = 2

1 X 1 = 1

1 X 2 = 2

0 X 1 = 0

2 X 2 = 4

9 X 1 = 9

6 X 2 = 12

0 X 1 = 0

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

1 X 1 = 1

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

1 X 1 = 1

0 X 2 = 0

0 X 1 = 0

0 X 2 = 0

2. Add the digits of the products together

E.g.: 6+4+1+0+6+1+4+8+1+8+2+1+2+4+9+1+2+1+1= 62

3. Divide by 10 and calculate remainder.

E.g. 62/10 = 6 with remainder of 2

4. Subtract remainder from 10 for the checkdigit.

E.g. 10 - 2 = 8  The checkdigit for the sample line is 8.