I have 13-digit GTIN, while your system requires 14 digits. What shall I do?

GTIN may consist of 8, 12, 13 or 14 digits, according to the kind of goods. Therefore, GTIN number under GS1 standards may be maximum 14 digits long, with preceding zeroes added to fill missing spaces on the left. Thus, a 13-digit GTIN shall have an added “0” in the beginning.