Note: Since VISA and MASTER
Cards are the most widely available cards, I have used them for my research.
But the results hold true for all card types.
Identifying Card Issuer Type
The first digit in a card represents the Major Industry Identifier and is known as MII digit. It represents the
category of entity which issued your credit card. There are following types of
issuers:
|
MII Digit
|
Issuer Type
|
|
0
|
ISO/TC 68 and other
industry assignments
|
|
1
|
Airlines
|
|
2
|
Airlines and other
industry assignments
|
|
3
|
Travel and
entertainment (such as American Express and Diners Club)
|
|
4
|
Banking and
financial (Visa)
|
|
5
|
Banking and
financial (MasterCard)
|
|
6
|
Merchandizing and
banking (Discover)
|
|
7
|
Petroleum
|
|
8
|
Telecommunications and
other industry assignments
|
|
9
|
National assignment
|
You can understand
this better by taking out your card and seeing the first digit. If you own a
petroleum card (such as those issued by Exxon Mobil or BP) then your card
number will start with 7. If you own a debit/credit card issued by a bank then
it will start with 4 or 5 (depending on whether it is a Visa card or Master
card).
Identifying Card Issuer
The first six digits in a card represent the issuer and is
known as Issuer Identification Number (IIN).
Below is a list of popular card issuers and their corresponding code:
|
Issuer
|
IIN
|
|
American Express
|
34xxxx, 37xxxx
|
|
VISA
|
4xxxxx
|
|
Master
Card
|
51xxxx-55xxxx
|
So
if you have a card that starts with 51 that means it is a Master Card.
Note: During my study I observed that Maestro card starts with 50 and 62. If you know something about Maestro cards, please share it through your comments.
Note: During my study I observed that Maestro card starts with 50 and 62. If you know something about Maestro cards, please share it through your comments.
Mathematically
speaking, there can be 10 raised to power 6 (since 6 digits are used to
identify an issuer), i.e. 1 million unique card issuers !!
Finding Account Number
Starting
from the seventh digit to second last digit, i.e., 7th to n-1 digit in a card represents
the account number. I noticed that this account number is not the same as your
bank account number. For cards issued by ICICI (whether VISA or MASTER Cards),
only first five digits of the card number and the account number matched, while
there was no such similarity for cards issued by HDFC bank.
Conclusion: 7th to n-1 digit in the card represents
the account number. This account number is not the account number of your bank
but the account number generated by the Card Issuer (such as VISA or Master
Card) to uniquely identify you.
A
card can have a maximum of 19 digits. So the account number can be a maximum of
12 digit number. That means each issuer can issue a maximum of 10 raised to the
power 12, i.e., 1 trillion cards !!
Check Digit
The last digit on the card is known
as the check digit and it determines whether it is a valid card or not.
With
that we come to an end on this interesting discussion about the numbers written
on a debit or credit card.
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