Frequently Asked Questions
What is a check digit?
A check digit is the last digit of a barcode that verifies the accuracy of the preceding digits. It detects input errors and scanning mistakes.
What is the difference between EAN-13 and UPC-A?
EAN-13 is a 13-digit international standard barcode, while UPC-A is a 12-digit North American standard. A UPC-A becomes EAN-13 compatible by adding a leading zero.
What algorithm is used to calculate the check digit?
EAN/UPC barcodes use the Modulo 10 (Mod 10) algorithm. Digits at odd and even positions are multiplied by different weights, summed, and the remainder from dividing by 10 determines the check digit.
Updated 2026 pricing