What Constitutes a Valid Credit Card Number?

Expectedly enough, those numbers you can see on any of your credit cards are not just random digits. They are written according to a certain algorithm, which is known as the Luhn algorithm. In this article, you will get to know what is the Luhn algorithm and what constitutes a valid credit card number, so you will actually be aware of what the numbers on your credit card mean.

Actually, the numbers from your credit card don’t only identify your account, but also provide a routing information. Thanks to this, the charges gets processed correctly every time you use your credit card anywhere. And now we will have a closer look at what those numbers signify.

What Constitutes a Valid Credit Card Number?

As a matter of fact, a typical credit card number can be divided into three parts: the first number, the middle number, and the last numbers. That’s the fact that will actually help us to understand what constitutes a valid credit card number easier. By understanding this structure of a credit card number, you will be able to generate your own valid credit card number.

Once you have grasped what each of those elements signifies in the overall structure of a valid credit card number (by reading about each of the elements below), you actually understand the entire structure of each credit card number. And you can easily find a proof that this method works. In order to find out what constitutes a valid credit card number, you can, for example, use the Credit Card Checker tool. Actually, that tool allows you to find out whether a particular credit card number is real or not.

What Constitutes a Valid Credit Number

Another tool that you can find on our website and you can take advantage of is the Credit Card Generator. Once you have learnt what constitutes a valid credit card number, you can create your own credit card number with ease. So, this tool can create a valid credit card number automatically by utilizing the above mentioned Luhn algorithm, so you don’t have to do it on your own.

The First Number of a Credit Card Number

As it was noted above, every credit card number is divided into three sections, and the first section of it is the very first (single) number. Actually, it is something similar similar to a phone code. When you call on a phone number beginning with +33, you probably know that you are going to call to France. Same stands for the credit card numbers, but in a bit different manner.

The first number of a credit card (this number is also known as MII, or major industry identifier) actually defines which major company issued your card. Typically, the credit card numbers started with a digit from 3 to 6. For instance, a Mastercard credit card should start with the digit 2 or 5, while Visa cards typically begin with the figure 4.

Here, for example, you can see the typical first numbers of the credit card numbers:

  • Mastercard: 2
  • American Express: 3
  • Visa: 4
  • Mastercard: 5
  • Discover 6.

But what about other figures, which are not included in this list? Well, the remaining figures are given to the cards of companies in other industries (i.e. those cards are not credit cards). For instance, the cards of health care and telecommunications companies start with the digit 8, while the first digit 7 is used by petroleum companies. If a credit card starts with a digit 1 or 2, it belongs to an airline company (don’t confuse it with airline credit cards, issued by banks!). After all, the digit 9 is reserved for national numbering systems, so any country may use it.

The Middle Numbers of a Credit Card Number

In order to gain an understanding what constitutes a valid credit card number, you should necessarily know about the middle numbers of every credit card number. Actually, they appear to be an important part of a credit card number and bear a certain meaning.

The first six numbers of any credit card number (including the first number, or the major industry identifier) are called as IIN, or the issue identification number. As you can understand from the name of these digits, they point to the bank or institution that issued a card. Certain numbers are attributed to a certain institution, so one may easily distinguish by what bank a card was issued with the help of these 6 figures.

The Last Numbers of a Credit Card Number

All the numbers of a valid credit card number except of the first 6 digits and the last digit are attributed to the account of a card holder. Those numbers are different than the person’s bank account number, but they help to understand to whom a particular credit card belongs. This way, you know now what constitutes a valid credit card number.

Above, however, there was mentioned the Luhn algorithm, which keeps these number running. Actually, this algorithm is used by the systems in order to verify whether a certain credit card number is valid. When you enter a credit card number on some website and mistake a certain digit in that card number, you immediately get an error, showing that you have just mistyped a credit card number. But, how the system is able to recognize it? It’s exactly thanks to this Luhn algorithm.

what contains a valid credit card number

The Credit Card Checker tool, which is available on our website and which was published above, utilizes the Luhn algorithm in order to check credit card numbers. Previously, it hasn’t been said what the last digit means. Actually, the Luhn algorithm utilizes the last digit as a check digit, i.e. uses it to make sure that a credit card number is typed correctly. The Luhn algorithm doesn’t tell you what constitutes a valid credit card number, but it actually allows you to check which credit card number is valid.

In order to use the Luhn algorithm, you don’t have to necessarily deploy a system or a tool. You can actually do it on your own and check whether a credit card number is valid. So, you need to make the following set of actions if you have a 16-digit credit card number:

  • The first thing you need to do is doubling every other digit of your credit card number. You should start from the very first digit and note down the results you have got.
  • If you have received double-digit results (for instance, 6*2=12), you should combine those figures (1+2=3) and use the resulting figures further.
  • Once you have combined all doubled digits into one-digit numbers, add all of them.
  • Get back to your credit card number. Add up all the digits you ignored, including the last digit.
  • Eventually, you should add the two sums that you have got.

If you have got a zero as a result, then you have done everything correctly and your credit card number is valid.

If you have a credit card with 15 digits (such as a credit card from American Express), you should just start doubling with the second digit of a credit card number – all the other instructions are the same. Now you don’t just know what constitutes a valid credit card number, but also how to check whether a particular card number is valid.

What Is the CVV Code?

The CVV code is also known as the Card Verification Value and this code is displayed on the flip side of your credit card. You are likely to know this code because you are asked this code whenever you make purchases online. The CVV codes of the majority of credit cards are 3-digit codes (Visa, Mastercard, Discover), while American Express sticks to 4-digit CVV codes.

The CVV code is needed to provide to online merchants. This way you actually prove that you physically possess the credit card. You should never confuse your CVV code with a PIN code that you use when getting cash at ATMs – these are two different codes! Your PIN code is private and shouldn’t be told to anyone.

The CVV code is also known under other names. For instance, for some customers this code is also known as the Card Security Code, or simply CSC. Additionally, there is also a CVV2 code – that is the same card verification value code, but it was created by a second generation process. That presumably makes it more difficult to guess that code.

Also, we recommend you to look at our website’s section of our Credit Cards and look for a credit card that suits your needs best.