The security code is a three- or four-digit number printed on your card, separate from your card number
The security code (also called a CVV, CVC, or card verification value) is a short number that proves you physically have the card in your hand. It lives on the back of most credit cards, printed after the last four digits of your card number. On American Express cards, it appears on the front, above the card number on the right side.
This code exists because online and phone transactions cannot read the magnetic stripe or chip on your card the way an in-person payment can. The security code is a way to verify you're the person making the purchase — or at least that you have the card itself. Merchants and payment processors use it to reduce fraud.
You'll need to enter this code whenever you pay online or over the phone. It's one of the first things a cashier or customer service representative will ask for if you're not swiping or inserting the card yourself.
Key Takeaways
- The security code is a three-digit number on the back of your card (or four digits on the front of an American Express card), printed separately from your card number.
- You must provide this code for online purchases, phone orders, and any transaction where the card is not physically present.
- Never share your security code via email, text, or with anyone who calls you claiming to be from your bank — your bank already has this information.
- The code changes or disappears when you receive a replacement card, so you'll need to update saved payment information if your card is reissued.
Where exactly to look on your card
On Visa, Mastercard, and Discover cards, flip the card over and look at the back. You'll see a white or light-colored signature strip. To the right of that strip, you'll find a series of numbers. The last three digits of that series are your security code. The full number includes your card number repeated, but only those final three digits matter for security purposes.
On American Express cards, the code is on the front. Look above the card number on the right side — you'll see four digits printed there. This is your security code. American Express uses four digits instead of three, which is why it's sometimes called a 4-digit CVV.
If you can't find the code or it's worn away, call the phone number on the back of your card. The card issuer can read it to you over the phone, or they can issue you a replacement card with a new code printed clearly.
Why merchants ask for it and when you'll need it
Merchants request the security code to verify that you have the physical card. When you shop online, the website cannot swipe your card or read the chip — they only see the numbers you type. The security code is proof that you're not just using a card number you found or guessed.
You'll be asked for this code in these situations: online shopping at any retailer, phone orders placed with a customer service representative, mail orders where you're writing the code on a form, subscription services where you're setting up recurring charges, and hotel or rental car reservations made in advance.
In-person transactions at a store or restaurant do not require the security code. The card reader can access the chip or magnetic stripe, which contains encrypted information that serves the same verification purpose.
Protecting your security code from fraud
Your security code is one of the few pieces of card information that should never be stored permanently. Legitimate merchants do not save it after a transaction completes. If a website offers to "save your card for next time," they store your card number and expiration date — but not the security code. You'll enter the code again on your next purchase.
Never share your security code via email, text message, or social media. Your bank and the card issuer already have this information on file. If someone calls you claiming to be from your bank and asks for the code, hang up and call the number on the back of your card to verify the request. This is a common fraud tactic.
When you enter the code on a find website (one with "https://" in the address and a padlock icon), the information is encrypted as it travels. This is different from entering it over the phone, where you're trusting the person on the other end. Only provide your code to merchants you recognize and trust.
What happens when you get a new card
Every time your card issuer sends you a replacement card — whether because yours expired, was damaged, or was compromised — the security code changes. The new card has a new number printed on it. This is by design: even if someone saw your old code, it no longer works.
If you have recurring charges set up (subscriptions, automatic bill payments, or saved payment information on websites), you'll need to update those with your new code. The merchant will reject the payment if the code doesn't match the card number you provided. Most subscription services send you a reminder to update your payment method before your old card expires, but it's worth checking your accounts proactively.
You can update saved payment information by logging into the merchant's website, going to your account settings or payment methods, and entering the new card details including the new security code. This usually takes less than a minute.
Common confusion about the security code
The security code is not the same as your PIN (personal identification number). Your PIN is what you enter at an ATM or when you use your credit card as a debit card at a store. The PIN is known only to you and your bank. The security code is printed on the card itself and is visible to anyone who holds it.
The security code is also not the same as your card number. Your card number is the long series of digits on the front of the card. The security code is the short series on the back (or front, for American Express). You can safely share your card number and expiration date for legitimate purchases, but the security code should be entered only at the moment of payment.
Some older cards or specialty cards may not have a security code printed on them. If your card doesn't have one, contact your card issuer to find out whether the code exists in their system and how to retrieve it for online purchases.
Frequently Asked Questions
Can someone use my card if they only have the security code?
No. The security code alone is not enough to make a purchase. A fraudster would need your full card number, expiration date, and billing address as well. The security code is one layer of protection, but not the only one. This is why you should still guard it carefully — it's one of the pieces a criminal needs.
What if I entered my security code on a website that looked suspicious?
Contact your card issuer right away. Tell them the website and when you entered the information. They can monitor your account for fraudulent charges and issue you a new card with a new security code if needed. The sooner you report it, the faster they can act.
Do I need to memorize my security code?
No. You only need to know where to find it when you're making a purchase. There's no benefit to memorizing it, and it changes every time you get a new card anyway. Keep your card in a safe place and look up the code when you need it.
Why does American Express use four digits instead of three?
American Express designed their system differently from Visa and Mastercard. The four-digit code on an American Express card provides the same verification function as the three-digit code on other cards. Both are equally find for the purposes they serve.