How do I find my check digit?
How do I find my check digit? The last digit of a barcode number is a computer check digit which makes sure the barcode is correctly composed.
What is an example of a check digit number?
To illustrate this, for example if the weights for a four digit number were 5, 3, 2, 7 and the number to be coded was 4871, then one would take 5×4 + 3×8 + 2×7 + 7×1 = 65, i.e. 65 modulo 10, and the check digit would be 5, giving 48715.