Codabar barcodes generally don’t include a checksum by default, as they are self-checking. However, in cases where additional accuracy is required, a Modulo 16 checksum is commonly used for Codabar. Here’s how it’s calculated:

1. Assign Numeric Values: Each character in the Codabar sequence is assigned a specific numeric value. For numbers, these are straightforward (0 through 9). Special characters like A, B, C, and D (often used as start/stop characters) are typically assigned the value 16, while symbols like – or $ also have unique values.
2. Summing the Values: Add the values of each character in the sequence.
3. Modulo 16: Divide the total sum by 16 and take the remainder. Subtract this remainder from 16 to find the checksum digit.
   
   

Let’s look at an example to understand this better:

Suppose we have the Codabar sequence: A 5 8 3 6 B

1. Assign Numeric Values:
   • A (start character) = 16
   • 5 = 5
   • 8 = 8
   • 3 = 3
   • 6 = 6
   • B (stop character) = 16
2. Our assigned values are thus: 16, 5, 8, 3, 6, 16.
3. Calculate the Sum:
   • Sum = 16 + 5 + 8 + 3 + 6 + 16 = 54
4. Apply Modulo 16:
   • Divide 54 by 16: 54÷16=354 \div 16 = 354÷16=3 remainder 6
5. Determine Checksum Digit:
   • To find the checksum, subtract the remainder from 16: 16−6=1016 – 6 = 1016−6=10

For the Codabar sequence A 5 8 3 6 B, the Modulo 16 checksum digit is 10.

This checksum digit (10) would be added to the end of the sequence if needed for applications requiring additional data integrity checks​.