Home Misc Tips To calculate the VIN check digit code use the following formula. STEP 1 Assign to each number in the VIN its actual mathematical value and assign to each letter a value based on the next chart. A=1 B=2 C=3 D=4 E=5 F=6 G=7 H=8 J=1 K=2 L= M=3 N=4 P=7 R=9 S=2 T=3 U=4 V=5 W=6 X=7 Y=8 Z=9 Q=8 STEP 2 Multiply the assigned value for each character in the VIN by the position weight factor specified in the following chart: VIN POSITION AND WEIGHT FACTOR: 1st=8 2nd=7 3rd=6 4th=5 5th=4 6th=3 7th=2 8th=10 10th=9 11th=8 12th=7 13th=6 14th=5 15th=4 16th=3 17th=2 STEP 3 Add the products from steps 1 and 2 and divide the total by 11. STEP 4 The numerical remainder is the check digit which would appear in the 9th position in the VIN. If the remainder is 10, then the letter “X” is used for the check digit.