### The Check Digit

borgo has done an excellent job of detailing the specifics on a VIN number and how they relate to what's actually on the vehicle or the options the vehicle has. Let's take a look at one of the lesser known numbers which make the whole thing work properly.

In position 9 of the VIN number is a character called a check digit. This character can be any number between 0 and 9, or X. To get this check digit, we preform the calculations below:

In our example, we'll use the VIN number JT2MA71N2M0155441
Don't worry, this vin is completely fictional, but correct. You can head over to carfax and punch it in and it should come back with 0 records.

Step 1:

First, convert every letter in the vin, to it's associated number. Any numbers in the original remain the same in their same place.

```A = 1; B = 2; C = 3; D = 4; E = 5; F = 6; G = 7; H = 8;
J = 1; K = 2; L = 3; M = 4; N = 5; O = 6; P = 7; R = 9;
S = 2; T = 3; U = 4; V = 5; W = 6; X = 7; Y = 8; Z = 9;
```

Step 2:

Now you must multiply each of the 17 digits in the vin by a set "weight" or multiplyer. The multiplyer is Position Specific.

```1st  = 8;  2nd = 7; 3rd  = 6;  4th = 5;  5th = 4; 6th  = 3; 7th  = 2;
8th  = 10; 9th = 0; 10th = 9; 11th = 8; 12th = 7; 13th = 6; 14th = 5;
15th = 4; 16th = 3; 17th = 2;```

Step 3:

After multiplying all of the digits by their weight, you should come out with a sum for each number. Add all of the sums together, then divide by 11. The remainder of the answer divided by 11 is the check digit. If the remainder is '10' the check digit is 'X'

Here's our example:

```VIN		J  T  2  M  A  7  1  N   2  M  0  1  5  5  4  4  1

Assigned Values	1  3  2  4  1  7  1  5   2  4  0  1  5  5  4  4  1
Multiplyer	8  7  6  5  4  3  2  10  0  9  8  7  6  5  4  3  2

SUM		8  21 12 20 04 21 02 50  00 36 00 07 30 25 16 12 02