The below algorithm is for calculating the last digit (check digit) of a MAWB.
Method of calculating the check digit
The MAWB number consists of a total 11 digits. These 11 digits can be divided into 3 parts
1] The first 3 digits are the Airline Prefix which are unique for every airline
2] The next 7 digits is the Serial Number of the AWB
3] The last digit is the Check digit
For example the AWB number is 176 1234567 5 Disregard the first 3 unique Airline Prefix numbers (Emirates etc) and the last Check Digit [because that’s what we are going to find and match it with the actual check digit]
Just consider the 7 digit Serial Number, 1234567 and divide this by 7 [the number 7 is a constant, Mod 7 ]
The remainder determines the Check Digit, For Example, Serial Number 1234567 when divided manually by 7 the remainder is 5. This remainder matches with the check digit of the AWB, hence the AWB number 176 1234567 5 is correct
Note : Since we are dividing the Serial Number by the constant number 7, the remainder will always be a number less than 7, i.e a number between 0 to 6.
For example If the remainder is 7, again it can be divided by 7 and the remainder will be 0 If the remainder is 8, again it can be divided by 7 and the remainder will be 1 If the remainder is 9, again it can be divided by 7 and the remainder will be 2 Hence, as a thumb rule, the check digit of an AWB number will always be a number less than 7.
The moment you come across the last number as 7, 8 or 9 instantly you can say that the AWB number is not valid.