 because there is no bar code or the bar code is unreadable).The decimal form is specified to be 18 digits grouped in a 5–5–4–4 pattern and is calculated by converting the manufacturer code portion (32 bits) to decimal and padding on the left with '0' digits to 10 digits and separately converting the serial number portion to decimal and padding on the left to 8 digits.A check-digit can be calculated from the 18 digit result using the standard base 10 Luhn algorithm and appended to the end.