How an air waybill number works
An air waybill (AWB) number has 11 digits, usually printed as XXX-XXXXXXXX:
- Airline prefix (3 digits). Assigned by IATA. It identifies the airline that issued the waybill — not always the airline that flies every leg, because cargo can be handed between partner airlines.
- Serial number (7 digits). The airline’s own running number for the shipment.
- Check digit (1 digit). The last digit, calculated from the serial number so that most typing mistakes are caught.
The check digit: divide by 7
Read the seven serial digits as one ordinary number, divide it by 7, and keep the remainder. That remainder is the check digit. The airline prefix is not part of the calculation.
Worked example with prefix 176 (Emirates(EK)) and serial 1234567: 1,234,567 ÷ 7 = 176,366 remainder 5 (7 × 176,366 = 1,234,562). So the check digit is 5 and the full air waybill number is 176-12345675. This is an example only — it is not a real shipment.
Because a remainder from dividing by 7 can only be 0 to 6, an air waybill number whose last digit is 7, 8 or 9 is always mistyped. The check catches many typing mistakes but not all of them (for example, changing a 0 to a 7 leaves the remainder the same), so a number that passes can still be wrong — but one that fails is definitely wrong.