MOD 10 Check Character Calculations

To calculate the MOD 10 check character (for domestic Express Mail only) for the PIC, follow the six steps explained below.

Digit positions are numbered from right to left for this calculation so that the MOD 10 check character position counts as position 1. For this example, assume that the PIC number is 12345678.

The MOD 10 check character is calculated using the following steps:

Step 1

Set up a two-row matrix, labeled 1 through 9, with 1 being the most significant position in the matrix (i.e., the right-most position). Starting from the least significant position of the matrix (position 9), copy each digit of the PIC all the way to position 2 (excluding the position of the check character shown in the example below by an “?”).

 

Position

9

8

7

6

5

4

3

2

1

PIC

1

2

3

4

5

6

7

8

?

Step 2

Starting from position 2 of the matrix, add the values in the even-numbered positions.

 

Position

9

8

7

6

5

4

3

2

1

PIC

1

2

3

4

5

6

7

8

?

For the example: 8 + 6 + 4 + 2 = 20

Step 3

Multiply the result of Step 2 by 3. For the example: 20 x 3 = 60

Step 4

Starting from position 3 of the matrix, add the values in the odd-numbered positions, skipping position 1 because it is the position of the check character.

 

Position

9

8

7

6

5

4

3

2

1

PIC

1

2

3

4

5

6

7

8

?

For the example: 7 + 5 + 3 + 1 = 16

Step 5

Add up the results for steps 3 and 4. For the example: 60 + 16 = 76

Step 6

The check character is the smallest number that, when added to the result obtained through Step 5, gives a number that is a multiple of 10.

For the example: 76 + 4 = 80; X = 4

The check character is 4, because 4 is the smallest number that, when added to 76, results in a multiple of 10. The shipping label ID would be “RB123456784US.”