How Many Digits are in a Credit Card?

Have you ever wondered how many digits are in a credit card? We’ll explore the different types of credit cards and how many digits are in each one.

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Credit Card Numbers

A credit card number is composed of two parts: the prefix and the account number. The prefix is the four to six digits that identify the card issuer. The account number is the individual account identifier. The credit card number is the most important part of a credit card.

How many digits are in a credit card number?

All credit cards have a number printed on them. This number is the card’s identification number, and it is used to track purchases and transfers. The number of digits in a credit card number can vary, but most cards have between 12 and 19.

What is the Luhn algorithm?

Credit cards and many other identification numbers are generated using what is called the Luhn algorithm. This algorithm is also known as the “mod 10” or “modulus 10” algorithm. The Luhn algorithm will generate a check digit that can be used to verify the accuracy of the credit card or ID number.

The Luhn algorithm is a simple mathematical formula that is used to generate the check digit. The check digit is the final digit of the credit card number and it is used to verify the accuracy of the rest of the number. The formula to generate the check digit is:

1) Double every second digit of the credit card number, starting with the second-to-last digit and moving backwards. For example, if your credit card number was 4111111111111111, you would double every second digit like so:
8 2 2 2 2 2 2 2 2 2
2) Add up all digits in resulting numbers and any other single digits you find in the credit card number (ignoring any doubled digits). So our example would become:
8+2+2+2+2+2+2+2+2 = 20
3) Find the next highest multiple of 10 from your total; in this case, it would be 20 (20 + 0 = 20). This multiple of 10 will be your check digit and you can now use this number to verify your credit card number by running it through this same process again!

Credit Card Types

There are four main types of credit cards: Visa, Mastercard, Discover, and American Express. Each credit card has a different number of digits. Visa and Mastercard have 16 digits, Discover has 15 digits, and American Express has 14 digits.


Visa cards are issued by banks and financial institutions all over the world and are accepted in more than 200 countries. Visa cards have either 13 or 16 digits and are divided into four distinct categories – consumer, business, corporate, and purchasing.

All Visa cards start with a 4. The first digit after the 4 indicates what type of Visa card it is – 8 for a business card, 9 for a corporate card. The second digit after the 4 indicates the country of issuance – 0 for all countries except the United States, which uses a 1.

The remaining digits make up the account number, which is assigned by the issuing bank or financial institution.


Mastercard is a credit card type that has 16 digits in the card number. The first digit is the “Major Industry Identifier” or MII. This is used to identify which industry the card belongs to. The next six digits are the “Issuer Identification Number” or IIN. These identify the specific issuer of the card. The next nine digits are individual account numbers, and the final digit is a check digit.


All Discover cards begin with the number 6. The length of the account number differs depending on the card type. Discover credit cards have 16 digits, while Discover debit cards have 19 digits. Additionally, the first six digits of a Discover credit card account number are the issuing bank identification number (BIN).

American Express

American Express (also called Amex) cards have 15-digit card numbers. The first two digits are the Major Industry Identifier (MII) — 34 for American Express, 37 for American Express Corporate. The next six digits are the Individual Account Number. The final digit is the check digit ( used to validate the card number).

Security Features

The number of digits in a credit card can vary, but most have between 12 and 16 digits. The number of digits in a credit card number is part of the card’s security features. The extra digits help to verify that the card is legitimate and that it hasn’t been tampered with.


The CVV number is the three- or four-digit number on the back (or front, in the case of American Express) of your credit card. This number adds an extra layer of security when you’re making online or phone purchases.

When you’re making a purchase online or over the phone, the merchant will usually ask for your CVV number as a way to verify that you have the physical card in your possession. This helps to prevent fraud and protects both the merchant and the cardholder.

If you’re ever unsure of whether or not a website is safe to input your CVV number, you can always call the customer service number on the back of your card and ask if it’s a valid site. Better safe than sorry!


Credit cards have a lot of security features, but one of the most important is AVS, or Address Verification System. This system verifies that the credit card number you’re using matches the billing address on file for that card. This helps to prevent fraud and protects both the credit card issuer and the merchant.

AVS checks are typically done by the credit card processor, not by the credit card issuer. That means that even if your credit card issuer doesn’t offer AVS, your transactions will still be protected. For example, Visa offers AVS protection for all transactions, even if the credit card issuer doesn’t offer it. Mastercard offers AVS protection for transactions in the US, Canada, and some other countries.

AVS is a free service, and there’s no need to sign up for it. When you make a purchase with your credit card, the merchant will send your information to the credit card processor. The processor will then check to see if your billing address matches the address on file for your credit card. If it does, then the transaction will be approved. If it doesn’t, then the transaction will be declined.

It’s important to note that AVS is not foolproof. If someone has your credit card number and knows your billing address, they may still be able to make unauthorized purchases with your card. That’s why it’s also important to keep an eye on your account activity and report any suspicious activity to your credit card issuer right away.

3-D Secure

3-D Secure is an authentication protocol that allows online shoppers to opt in to verified by Visa or MasterCard SecureCode when making a card-not-present transaction. This extra layer of security is designed to reduce fraud and protect cardholders by authenticating the cardholder’s identity during the transaction.

When a shopper opts in to 3-D Secure, they will be prompted by their bank to enter a one-time code or password that has been assigned to them. This code is typically sent via SMS or generated by an app on the cardholder’s mobile device. Once the code has been entered, the transaction can proceed as normal.

If the cardholder does not have a one-time code or password, they can still complete the transaction without 3-D Secure. However, they may be liable for any fraud that occurs as a result of the transaction. For this reason, it’s generally advisable to opt in to 3-D Secure when it is offered.

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