Barcode check digit

|The last number on a barcode is the check digit. This is calculated based on the rest of the code and is read in by the reader. When the barcode is read the computer will re-calculate the check digit and then will compare the result with the check digit it read in. If they differ then a error must of occurred and as such the barcode will be rejected.

A check digit is calculated by -

1. Finding the sum of all of the individual digits.
2. Dividing the result by 10 and taking the remainder

The remainder will become the check digit. Sometimes a weight is used for each digit however you do not need to use weights when calculating barcodes for the exam.