What do credit card numbers mean?

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Credit card numbers actually aren’t random at all.

Credit card numbers each serve a particular function that determines how each transaction will be routed and enhance security.

You probably know your credit card numbers by heart, either in full or the last four digits. But, if you are like most people, you probably have no idea what they mean. The numbers each have a specific identification function either for the bank, the system or you personally. While it is not imperative you know what the numbers mean, understanding the process your information goes through with each credit card transaction is still food for thought.

Unlike other account numbers, like those of the gas or phone company or even department stores, credit cards all use the same number system. In this system, the number and structure of the numbers on the card indicate what kind of card it is and to whom it belongs.

Credit card numbers breakdown

The first number on your credit card is called the Major Industry Identifier (MII) and notes the system that your card belongs to.

  • Number 3 denotes an American Express
  • Number 4 denotes a Visa
  • Number 5 denotes a Mastercard
  • Number 6 denotes a Discover credit card

Within each card system is a structure that is unique to that credit card company. For example:

  • On American Express cards, the third and fourth digits are the type and currency, the fifth through the eleventh digits are the account number, the twelfth through the fourteenth digits are the cards number within that particular account and the fifteenth digit is the check number.
  • A Visa uses digits two through six for the bank number, the seventh digit through the twelfth or the fifteenth are the account number and digit thirteen or sixteen is the validator number.
  • Mastercard uses digits two through six as account numbers depending on the length it can be digits two and three or two through four or two through five or six. After the bank number, the digits that follow up to the fifteenth are the account number and the sixteenth digit is the validator number.

Compare credit cards

Name Product Filter values Rewards Purchase APR Annual fee
Blue Cash Everyday® Card from American Express
2% at US gas stations and select US department stores, 3% at US supermarkets on up to $6,000 per year, then 1% after that and on all other purchases
0% intro for the first 15 months (then 13.99% to 23.99% variable)
$0
Get 3% cash back on groceries on up to $6,000 annually (then 1%) with no annual fee. This is a simple and effective rewards card. Rates & fees
Chase Sapphire Preferred® Card
5x points on Lyft, 2x points on travel and dining and 1x points on all other purchases
15.99% to 22.99% variable
$95
Earn a huge signup bonus worth $$1,000 with this popular travel card. Combine with other Chase Ultimate Rewards cards for even greater value.
Chase Freedom Flex℠
5% back in rotating categories up to $1,500 combined each activated quarter (then 1%), 5% on travel purchased through Chase, 3% on dining and drugstores, and 1% on all other purchases
0% intro for the first 15 months (then 14.99% to 23.74% variable)
$0
Get up to 5% cashback in rotating and newly added everyday categories. The refreshed Freedom Flex card has lots of earning potential.
Citi® Diamond Preferred® Card
N/A
0% intro for the first 18 months (then 14.74% to 24.74% variable)
$0
An impressive 18 months intro APR on balance transfers and purchases, as well as no annual fee make this one of the top 0% APR cards available.
Blue Cash Preferred® Card from American Express
6% on select US streaming services, 3% on transit and US gas stations, 6% at US supermarkets on up to $6,000 annually, then 1% after that and on all other purchases
0% intro for the first 12 months (then 13.99% to 23.99% variable)
$95
Perfect for families: Get up to 6% on everyday purchases and a welcome offer worth $250. This heavy-hitter rewards card has uncontested value. Rates & fees
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Bottom line

While it is more important to know where you are spending your money than the function of your credit card numbers, it is helpful to understand the complexities of the credit card system. Once you realize how much effort has gone into ensuring security and efficiency you will have more appreciation for your card.

If you’re looking for a new card, make sure to compare your credit card options to find the best fit for your wallet.

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