Test Credit Card Account Numbers

1. Prefix, Length, and Check Digit Criteria
    
   Here is a table outlining the major credit cards that you might want to validate.
    
   CARD TYPE Prefix Length Check digit algorithm
   MASTERCARD 51-55 16 mod 10
   VISA 4 13, 16 mod 10
   AMEX 34
   37 15 mod 10
   Diners Club/
   Carte Blanche 300-305
   36
   38 14 mod 10
   Discover 6011 16 mod 10
   enRoute 2014
   2149 15 any
   JCB 3 16 mod 10
   JCB 2131
   1800 15 mod 10
    
   
2. LUHN Formula (Mod 10) for Validation of Primary Account Number
   

The following steps are required to validate the primary account number:
 
Step 1: Double the value of alternate digits of the primary account number beginning with the second digit from the right (the first right--hand digit is the check digit.)
 
Step 2: Add the individual digits comprising the products obtained in Step 1 to each of the unaffected digits in the original number.
 
Step 3: The total obtained in Step 2 must be a number ending in zero (30, 40, 50, etc.) for the account number to be validated.
 
For example, to validate the primary account number 49927398716:
 
Step 1:
 
4 9 9 2 7 3 9 8 7 1 6
x2 x2 x2 x2 x2
------------------------------
18 4 6 16 2
 

 

Step 2: 4 +(1+8)+ 9 + (4) + 7 + (6) + 9 +(1+6) + 7 + (2) + 6
 
Step 3: Sum = 70 : Card number is validated
 
Note: Card is valid because the 70/10 yields no remainder.
 
Source: http://www.beachnet.com/~hstiles/cardtype.html[^]