Concepts

Products

Contacts

Home

Site Index

Reminder: This is what a valid VR looks like

R36IJ GLVNY IN215 ZRHQZ WL1IA

The check digits at the end of each group of 5 are calculated using "modulo arithmetic".

Add the ASCII values of the first four characters. Divide the result by 35 (the number of permitted characters) and convert the remainder back into one of the permitted characters.

Repeat that for the 10th character - except that the sum includes the first 9 characters, so that the check digit is now confirming the validity not just of the second group of 5 characters, but the first two groups as well.

Repeat for the 15th, 20th and 25th characters.