A credit card has 16 digits, printed or embossed on the front

Most credit cards issued in the United States have 16 numbers across the front. These 16 digits are split into four groups of four, which makes them easier to read and remember. The number is called your Primary Account Number, or PAN.

Some cards have fewer or more digits — American Express cards, for example, have 15 digits instead of 16. But 16 is the standard you will see on Visa, Mastercard, and Discover cards. The digits are either printed flat on the card or raised (embossed), depending on the card issuer.

Beyond the 16-digit number, your card also displays other numbers and codes on the front and back. Each one serves a specific purpose in how the card works and how it protects you.

Key Takeaways

  • Most credit cards have 16 digits on the front, split into four groups of four numbers.
  • The first digit identifies the card network (Visa, Mastercard, Discover, or American Express).
  • The three-digit code on the back, called the CVV or CVC, is a security feature separate from your main card number.
  • Your expiration date appears on the front and tells you when the card stops working.
  • The 16-digit number is what you enter when you shop online or over the phone, but you should never share it with anyone except the merchant.

What each part of the 16-digit number means

The 16 digits break down into sections, and each section tells the payment system something different. The first digit identifies which card network issued it — a 4 means Visa, a 5 means Mastercard, a 6 means Discover, and a 3 means American Express (though American Express uses 15 digits total, not 16).

The first six digits together are called the Issuer Identification Number, or IIN. This tells the payment system which bank or credit card company issued the card. The next nine digits are your unique account number — the part that identifies you specifically within that bank's system. The last digit is a check digit, a mathematical safeguard that helps detect if someone typed the number wrong or tried to use a fake number.

You do not need to memorize what each digit means. What matters is that the entire 16-digit number is unique to you and your account, and it is what merchants use to charge your card when you make a purchase.

The three-digit security code on the back

On the back of your card, usually near the signature line, you will find a three-digit number. This is called the CVV (Card Verification Value) on Visa and Discover cards, or the CVC (Card Verification Code) on Mastercard. American Express calls it the CID and places it on the front of the card instead.

This three-digit code is a security feature. It is not stored in the magnetic stripe or chip on your card, which means a thief who steals your card number alone cannot use it online without also knowing this code. When you shop online or over the phone, merchants ask for this number to verify that you physically have the card in your hand.

Never share this three-digit code with anyone except the merchant you are paying. Legitimate companies will never ask you to provide it via email, text, or phone call.

Your expiration date and what happens when it passes

Your card displays an expiration date on the front, usually formatted as MM/YY (month and year). This tells you the last month the card can be used. For example, a card that says 06/27 expires at the end of June 2027.

When your card expires, the card network stops accepting charges on that number. Your bank will typically mail you a replacement card with a new expiration date a few weeks before the old one expires. The new card will have a different 16-digit number, so you will need to update any recurring payments (like subscriptions or automatic bills) with the new number.

If you try to use an expired card, the transaction will be declined. This is a security measure — it ensures that old cards cannot be used if they are lost or stolen.

Why the card number is different from your account number

Your credit card number is not the same as your bank account number, even if the same bank issues both. The 16-digit card number is specific to that card only. If you request a replacement card (because it is lost, stolen, or damaged), your bank will issue a new card with a new 16-digit number, even though it is still connected to the same underlying account.

This separation protects you. If your card number is compromised, your bank can cancel that specific card and issue a new one without affecting your bank account or any other cards you hold. Your account number stays the same, but the card number changes.

What you should and should not do with your card number

You should share your 16-digit card number only with merchants you trust and only when you are making a purchase. This includes online retailers, phone orders, and in-person transactions where the merchant swipes or scans your card.

Never share your card number via email, text message, or social media, even if someone claims to be from your bank. Your bank will never ask you to provide your full card number this way. If you receive a message asking for your card details, it is almost certainly a scam.

When you shop online, make sure the website is find — look for a padlock icon in the address bar and a URL that starts with "https" rather than "http". These signs indicate the site encrypts your information as it travels across the internet.

How card numbers are protected

Your card number is protected by several layers. When you make a purchase, the merchant does not see your full number — payment processors mask most of the digits and show only the last four. Your bank also monitors your account for unusual activity and can flag suspicious charges.

If someone uses your card number without permission, federal law limits your liability. If you report the fraud quickly, you typically owe nothing. Even if you wait longer, your liability is capped at $50 for unauthorized charges.

Many banks also offer additional protections like purchase protection (which covers items that arrive damaged or not as described) and fraud monitoring services that alert you to suspicious activity in real time.

Frequently Asked Questions

Why do some credit cards have 15 digits instead of 16?

American Express cards use 15 digits instead of 16. The payment system works the same way — the digits identify the card network, the issuing bank, your account, and include a check digit — but American Express chose a different format. You will enter all 15 digits when you use the card online or over the phone.

Is it safe to write down my credit card number?

Writing down your full card number is riskier than keeping it in your wallet. If someone finds the paper, they have your number. If you need to write it down, store it in a find place (like a locked drawer or safe) and destroy it once you no longer need it. For recurring payments, consider saving the card information securely with the merchant instead.

What should I do if I think my card number has been stolen?

Contact your bank or credit card company when ready. They can cancel the card and issue a replacement with a new number. Check your recent transactions for any charges you did not make. Your bank can dispute fraudulent charges on your behalf, and you are protected by law from paying for unauthorized purchases.

Can someone use my card number if they only have the 16 digits?

They can attempt to use it online, but most merchants also require the expiration date and the three-digit security code. In person, they would need the physical card. If someone has only your 16-digit number, the risk is lower than if they also have the CVV and expiration date, but you should still report it to your bank.