What Do The Numbers on My Card Mean?

All credit and debit cards are printed with certain numbers at the back or front sections that can be quite confusing to understand. Generally, these figures provide information about the card’s issuer, registered financial institutions, account details and security codes. When you enter your card into an ATM machine for cash withdrawal, each of these numbers is used for validation and identifying the user before money is availed.

Nowadays, card numbers have been configured to follow the ISO/IEC 7812-1:2006 standardization format which was first implemented in 1989. It allows owners to use their cards in any ATM around the world and still be recognized.

Below is a short summary of the card numbers and what they actually mean:

I) Issuer Identifier Digits

These are the first six numbers found on your card. The first digit (1) is typically used to identify the card’s original manufacturer. For instance, if the first digit is 4, 5 or 6 then it means that the issuer is a banking or financial company. As for 2 – 6, the numbers typically identify a particular business that has been assigned the card for issuance to its clientele.

Moreover, some companies may have multiple identifier numbers for different cards that they offer to customers. For instance, a single bank may provide debit and credit card users with distinct numbers, even though it’s the same institution that’s providing these unique digits. These first 6 digits of a card were initially referred to as bank identification number or BIN, but the name was later changed to issuer identifier number (IIN) as institutions other than banks began providing the cards as well.

II) Unique Individual Identifier

They are the numbers starting from 7-15 which pinpoint to the unique account holder. These digits are usually provided by the card issuer which may be a bank or any other financial institution, and are distinct to them alone. There are no two institutions that can have the same sequence for their Unique Individual Identifier (UII) number.

III) Check Digit

This is the very last figure found on your card, also known as digit 16. It’s typically used to evaluate the precision of card numbers and is calculated based on the public domain system known as Luhn algorithm. It confirms that the card number wasn’t wrongly added by the issuer when making phone or digital payments, which makes it a vital component in card processing.

Typically, credit-card digits are keyed in, input, transmitted and quoted by the ATM machine before being accepted. However, this process may sometimes have errors especially if it’s humans who processed the numbers in the first place and not a computerized system. To reduce such problems, cards use the last check-digit which is calculated by multiplying every even-position figure starting from the right by two.

In case the final result is a double-digit figure, then they are added together to come up with one number known as the digital root. Once this sum is arrived at, all the remaining odd-position numbers are also added onto it. Ultimately, the check digit is the particular number that needs to be summed up to this figure to arrive at the nearest multiple of 10, meaning that when divided by 10 the figure has no remainder. For instance, if the sum of the digital root and odd numbers is 72, then the card’s check number would be 8 since that’s the nearest number needed to make it a multiple of 10.

Specific Card Issuers & Their Identifier Numbers




All cards beginning with the number 4 belong to Visa, whereas the 2nd to 6th numbers belong to the financial institution that the card was assigned to. Though in the past there were some Visa cards with only 13 numbers, times have changed and nowadays most of them follow the 16-digit pattern. In any Visa card format, your personal account number starts from the 7th up to 15th digits, while the final number is the check digit.

Master Card

As for MasterCards, they all begin with the number 5 and the whole sequence is usually a 16-digit integer. Moreover, the 2nd and 3rd, 4th or 5th figures on the card represent the bank number, while every other digit up to 15 is the user’s account details followed by the check number at the end.

American Express

Unlike Visa and Mastercard, American Express is the only financial institution that uses 2 unique starting numbers for their cards, which are 34 and 37. Both of these digits act as the company’s identity numbers, while the 3rd and 4th numerals tell what type of card it is, whether debit or credit, as well as the currency being used.

As from number 5 to 11, it’s the card-holder’s personal account details while the 12th, 13th and 14th figures reveal the card number account. Finally, the last digit on the American Express Card is the check number, which is found on all other types of cards and protects against technical errors and fraud attempts by criminals who may be in possession of your banking details.

Primary Account Number

Nowadays, card numbers are not only issued to financial institutions such as banks, but also to other private bodies such as telephone service providers, department stores, airlines and healthcare centers. When used in such settings, the private label cards often contain a primary account number that identifies the issuer and the account holder as well. Nevertheless, in most cases it’s only these private institutions that accept the use of their cards within their own premises, which may be found within a specific geographical region or have branches nationwide.

It’s common practice nowadays for the Primary Account Number (PAN) to be imprinted on the front section of these cards, where they can be scanned by a machine at the point of retail to identify the particular user. The stamped PAN historically represents the card number’s original purpose of being transferred onto receipts, during the days when cards were physically processed using the flatbed imprinter.

Over the recent few years, there’s been a sharp increase in the number of card providers and this is expected to result in a decline in issuer identifier numbers (IIN) within the next short period of time. Consequently, various regulatory bodies such as International Electrotechnical Commission (IEC) and the International Organization for Standardization (ISO) have sought to revise the standards required for identification cards. These bodies have come up with a resolution that IIN numbers should be increased from 6 to 8 digits, a move that would possibly increase IIN digits from just 1 million to 100 million. Nevertheless, the overall length of PAN numbers shall still continue to be 10 to 19 figures long, as used by most retail institutions and other companies that issue cards.

Typically, a single IIN can be configured for use on several 100,000s of private cards, based on the overall length of the whole credit card numeral. The usual length of a primary account number is 16 digits, of which 6 comprise of the issuer identifier number and the final one the check-sum figure. This simply means that a total of 9 numbers remain to be allotted to private user accounts, summing up to an average of 1 billion possible new accounts for every IIN. Moreover, any likely combinations in the figures aren’t used per account, and the numbers are typically given spontaneously without any patterns so as to minimize the chances of fraudulent attacks.

The American National Standards Institute

All card numbers issued by credit firms are developed using a unique formula created by the American National Standards Institute. It’s a private regulatory agency that was founded in 1918, with the goal of promoting consensus standards, conformity assessment structures and ensuring integrity of systems.

ANSI has a broad membership comprising of federal institutions, companies, international organizations, academic institutes and professionals. Currently, the organization has well over 270,000 firms that help provide guidance and advice on how to help develop or streamline card numbers, including more than 30 million professionals globally who also serve the same role.

Additionally, ANSI is affiliated to the global Organization for Standardization (ISO), which is mandated with regulating the quality of various products around the world including cards.

Basically, when card companies are adding numbers onto their cards, they don’t just pick them randomly but actually use a special formula to come up with unique strings of integers that bear certain meaning and have utilitarian purpose. These numbers confirm that the card being used is legit and has passed all the quality controls established by regulatory agencies such as ANSI.

Since most card providers such as Visa, Mastercard and American express are from the USA, they must all comply to ANSI standards when formulating their card numbers so that they can be acceptable for use by the public. The organization is also actively involved in assessment of competence and accreditation of these card companies, to ensure that they always maintain appropriate standards in the manufacturing of their cards and the numbers they bear.

In Short:

Card numbers are unique integers that identify the manufacturer, issuing company and user account details which are all necessary for a secure transaction. They are also unique to each card provider such as Visa, Mastercard or American Express

This article can be considered as a continuation on the subject from our previously published article about the SWIFT, BIC, IBAN, Routing Number and Sort Codes.

Notify of

Inline Feedbacks
View all comments
Would love your thoughts, please comment.x