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What Every User Should Know About Credit Card Numbers [A Comprehensive Guide]

Ashley Ferraro, Product
Aug 21, 2023
 Min Read

Credit cards have become the go-to payment method in the nation. According to a Statista 2022 study, the U.S. has roughly three times more credit cards than debit cards in circulation. In some cases, you don’t even need a physical credit card to complete payments—having just the credit card numbers is enough for online payments.

Credit card numbers may seem random, but they are a carefully structured set of digits and the backbone of a payment process. In this guide, you can learn:

  • Where is the credit card number?
  • What do the numbers on a credit card mean?
  • How can you know if a credit card number is real and valid?

We will also cover the risks of using credit cards online and discuss ways to reduce vulnerabilities.

What Is a Credit Card Number, and How Does It Help Complete Payments?

A credit card number is a unique 13- to 19-digit sequence printed or embossed on a typically plastic card. The numbers are not random but follow uniform international standards set by the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO)[1]. They hold crucial information related to the card, such as:

  • The credit card issuer (bank or company)
  • The credit card network (Visa®, Mastercard®, American Express®, Discover®, etc.)
  • The user account number associated with the card

The credit card number helps a payment processor assess if the card is legitimate and authorized. When a customer initiates a payment, the card credentials are verified across the card network. After the verification, the payment request is sent to the customer’s credit card company or bank. Once the issuing institution authorizes the payment, the requested credit is extended to the customer, enabling the merchant to receive the funds.

A closeup shot of a woman’s hand swiping a black payment card through a card reader

Source: Mark OFlynn

How Long Is a Credit Card Number?

Most payment card numbers are 16 digits long and grouped in blocks of four digits. Still, credit cards may have anywhere between 13 and 19 digits[2], depending on the card issuer. Here are some examples[2]:

Card Issuer
Credit Card Number Length
13, 16, or 19
American Express®
16 or 19
Diner’s Club®
14 or 16

Among the major credit cards in circulation, only American Express cards have a non-standard 15 digits. Amex card numbers are grouped in three blocks of four, six, and five digits, i.e., they’re printed like this: XXXX-XXXXXX-XXXXX.

Where To Find the Credit Card Number

Like prepaid or debit card numbers, credit card numbers are typically located on the front of the card, often toward the center. Some card companies print them on the back to conceal the numbers from common view.

If you cannot access your card, you can usually find the number through your financial institution’s internet banking[3] portal, a service most card companies offer. The card number is usually displayed under the My Account or similar tab. You may also find your credit card number on your monthly statement. Note that you may not find the entire sequence as most issuers only mention the last four digits for security reasons.

Meaning of Credit Card Numbers—Explained

A standard credit card number follows a similar structure worldwide. Here’s how it works:

  1. The first six (or sometimes eight) digits represent the Issuer Identifier Number (IIN).
  2. The next nine to twelve numbers identify the individual customer account.
  3. The last digit is the checksum.

The First 6 or 8 Credit Card Digits—Issuer Identifier Number (IIN)

The IIN, also called the Bank Identification Number (BIN), identifies the bank or company linked to your credit card. In the case of large financial institutions, the number also contains other essential data, for example, the country where the card was issued[3].

The first digit of the IIN represents the Major Industry Identifier (MII) that identifies the card network and the attached industry. Refer to the table below for examples[4]:

Credit Card Network
Banking and financial
Banking and financial
American Express
Entertainment, travel, and banking
Merchandising, banking, and financial
Diner’s Club
Entertainment, travel, and banking

You can use the online Credit Card BIN Checker to check the institution related to a particular number.

The Next 9–12 Credit Card Digits—Individual Account Number

Except for the last digit, the remaining digits after the IIN are linked to the user’s credit card account number with the bank or company. These digits are individual to each cardholder. The account number is typically nine digits long on a 16-digit card but may vary depending on the total digits.

A digital illustration of a credit card mockup representing the card number, expiration date, and username placeholders

Source: JJuni

The Last Credit Card Digit—Checksum

The last digit of a credit card number is the checksum that helps verify a card’s validity. The checksum formula is based on the Luhn Algorithm that mathematically validates if a card number provided is in the correct sequence.

If you suspect a credit card number is fake, you can verify the sequence using the Luhn Algorithm. Here are the four steps:

  1. Put the credit card number in a table (refer to the table below to see how we’ve done it).
  2. Once done, start doubling every other digit starting from the right side (excluding the checksum). If you’re handling a 16-digit credit card number, skip digit 16 and double the digit at slots 15, 13, 11, and so on.
  3. Some of the doubled digits will be greater than 9. In such cases, add the individual ciphers from the doubled digit to make a new total. For example, if one of the doubled digits is 12, change it to 1+2, i.e., 3.
  4. Add the digits from Step 3 with those that were not doubled—if the sum is a multiple of 10, for example, 50 or 70, the credit card number is valid.

The process will be easier for you to grasp by checking the example. The table below illustrates the calculation with a sample number 4388-5760-1841-0707, 7 being the check digit:

A table calculating the validity of the checksum on a credit card using the Luhn Algorithm

Since the sum of the final set of digits is 70 (divisible by 10), the sample credit card number is valid. Remember that the checksum can only verify the mathematical input—the algorithm can neither detect malicious attacks nor tell if the card is stolen or expired.

How Safe and Reliable Are Credit Cards

The structure of card numbers and transaction protocol play a big part in making credit card payments reliable, convenient, and error-free, but they cannot prevent fraudulent activities entirely. Taking additional steps to protect your card numbers is essential because credit card fraud is currently on the rise.

According to a forecast reported by Insider Intelligence, card fraud losses (all card types included) are expected to reach $13.73 billion by 2024. Here are some practical tips to follow:

  • Turn on fraud alerts—Most banks and credit card companies offer users the option to get notified of transactions by enabling fraud alerts. That way, you can quickly detect any suspicious activity on your card.
  • Keep your physical card safe—Take steps to protect your payment cards from physical theft. The loss of debit and credit cards may lead to fraudulent transactions and identity theft.
  • Use a virtual card online—While protecting a physical card is relatively simple, keeping it safe online isn’t as straightforward. Card data can be stolen from merchant websites due to security breaches, so sharing your real credentials for online purchases can be risky. A virtual card linked to your bank account or card reduces the risk of data exposure by replacing your actual card details with randomly generated numbers. Even if the website suffers a data breach, the hacker cannot access your actual credit or debit card information because the virtual card number masks it.

A focus on payment security due to increasing card fraud has boosted the use of virtual cards as a payment method. According to Future Market Insights, the virtual card market size is expected to be worth $1.3 trillion by 2032.

Make Your Digital Payments Safer—Use Privacy Virtual Cards

If you want a reliable virtual card provider, consider Privacy. Like regular physical cards, Privacy Virtual Cards have unique 16-digit card numbers, expiration dates, and security codes that can be used for online shopping. Privacy Cards are issued in Mastercard or Visa networks and work at most vendors that accept debit/credit cards.

Here’s what the signup process entails:

  1. Go to the Sign Up page (alternatively, you can download Privacy’s Android or iOS app)
  2. Fill out the mandatory Know-Your-Customer (KYC) details
  3. Link your U.S. bank account or debit card
  4. Request your virtual card

Besides offering additional security, Privacy expedites checkouts through Chrome, Firefox, and Safari browser extensions. These extensions enable you to:

  • Create a unique Privacy Card directly on the payment screen.
  • Autofill the details into the checkout field to reduce manual error.
A shot of a laptop on a white surface displaying the symbol of an e-commerce cart on the screen

Source: QuinceCreative

With Privacy, you can make online payments safer by creating Merchant-Locked Cards. Once your Privacy Card is created, it will lock to the first merchant you use it at—any purchases at other merchants will be declined. The feature prevents card misuse if your payment data is breached on the vendor’s website.

Privacy also offers Single-Use Cards that close after the first transaction, rendering them useless to a potential thief. This type of card is best for using with merchants you don't fully trust or don't plan to shop with again.

Benefits of Using Privacy Cards

Privacy Cards offer more than online payment security—they come with practical budgeting features.

You can customize each Privacy Card with spending limits to avoid exceeding your budget. Here are some scenarios where limits are necessary:

  • If you share a virtual card with a trusted family member or a business employee, the limit ensures you control their spending.
  • In case you used a Privacy Card for recurring subscription payments, the limit will prevent the merchant from imposing fees you are unaware of.

Privacy also allows you to close or pause your virtual cards if you want the platform to deny payments on a particular card. Closing a Privacy Card deactivates it permanently, while paused cards can be unpaused. If you’re closing a card used for a recurring subscription, the action will decline the charges.

A person holding a cup of coffee while using a laptop on a white table

Source: Cup of Couple

Privacy currently offers the customizations mentioned above at no additional cost to the user. Privacy is free for domestic transactions and the base tier lets you create up to 12 new virtual cards monthly. If you require more cards, opt for the Pro ($10/month) or Teams ($25/month) plan. Paid users can also claim 1% cashback on eligible transactions totaling up to $4,500 per month—check out the details here

Is Privacy Safe?

Privacy is a PCI-compliant company providing the same level of security as the most reliable financial institutions. To make monitoring easy, the platform enables push notifications for all account activities—such as a new transaction or a declined payment. Privacy’s dashboard lets users check their transaction history and detect if anything’s amiss.

Accredited by Better Business Bureau®, the company holds itself to the highest standards and offers an excellent customer support system.


[1] Chase., sourced May 2023
[2] Staff. Growing Savings., December 6, 2017
[3] Card Insider., November 25, 2022
[4] Staff., May 24, 2018

Privacy — Seamless & Secure Online Card Payments
Checkout securely online by creating unique virtual card numbers for every purchase. Avoid data breaches, unwanted charges, and stolen credit card numbers.
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Privacy — Seamless & Secure Online Card Payments
Checkout securely online by creating unique virtual card numbers for every purchase. Avoid data breaches, unwanted charges, and stolen credit card numbers.
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Privacy virtual cards
Spending Limits

Set a spending limit, and Privacy will block all charges that go over the limit

Merchant-Locked Cards

Lock your Privacy card to one merchant you frequently shop from

Single-Use Cards

Secure your one-time payments to websites whose trust worthiness you're unsure of

Pause/Close Cards

By pausing or closing a card, Privacy will block all future transactions

Get a Privacy Card Now
Privacy — Seamless & Secure Online Card Payments
Checkout securely online by creating unique virtual card numbers for every purchase. Avoid data breaches, unwanted charges, and stolen credit card numbers.
Sign Up
Privacy — Seamless & Secure Online Card Payments
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