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 printed on the back of most credit cards. For Visa, Mastercard, and Discover cards, it's a three-digit number printed to the right of the signature strip. For American Express cards, it's a four-digit number printed on the front, above and to the right of your card number.
This code exists so that online and phone merchants can verify you actually have the physical card in your hand. When you enter it during checkout, the merchant sends it to your card issuer, who confirms it matches their records. If the numbers don't match, the transaction is declined.
The security code is not the same as your PIN (the number you enter at an ATM or store terminal). It's also not your card number or expiration date. It's a separate piece of information that only appears on the card itself — not on receipts, statements, or anywhere else your card details might be stored.
Key Takeaways
- Visa, Mastercard, and Discover cards have a three-digit security code on the back of the card, to the right of the signature strip.
- American Express cards have a four-digit security code on the front, above and to the right of the card number.
- You need the security code whenever you make an online purchase or pay over the phone with a credit card.
- Never share your security code with anyone except the merchant you're paying, and never write it down or store it digitally.
How to locate the security code on the back of your card
Turn your card over so you're looking at the back. At the bottom right, you'll see a white or light-colored box with a series of numbers printed in it. This is the signature strip. To the right of this box, you'll see three digits printed directly on the card itself. Those three digits are your security code.
The three digits appear after the last four digits of your card number, which may also be printed on the back. Make sure you're reading the three digits that come after your card number, not part of the card number itself. If you're having trouble spotting it, the numbers should be slightly raised or embossed compared to the card surface.
How to locate the security code on an American Express card
American Express cards are formatted differently. Flip your card to the front and look above and to the right of your 15-digit card number. You'll see a four-digit number printed there. This is your American Express security code, sometimes called a CID (Card Identification Number).
The four digits on an American Express card are always on the front, never on the back. This is one of the clearest ways to tell an Amex card apart from other credit cards. If you only see three digits on the back of your card, it's not an American Express card.
When you need to enter your security code
You'll need your security code for any transaction where the merchant can't physically swipe or insert your card. This includes online shopping, phone orders, and mail orders. When you're checking out on a website, there's usually a field labeled "CVV," "CVC," "Card Security Code," or "Security Code" where you enter it.
You do not need to enter your security code when you use your card in person at a store or gas pump. The card reader reads the information directly from the magnetic stripe or chip, so the code isn't required. You also don't need it when you use your card at an ATM to withdraw cash.
Some subscription services and recurring payments may ask for your security code when you first set up the payment, but they should not ask for it every time they charge you. If a merchant asks for your security code repeatedly, that's a sign something may be wrong.
Why merchants ask for the security code
The security code is a fraud prevention tool. When you provide it, the merchant knows you have the physical card — not just the card number, which could be stolen or guessed. A thief who has your card number and expiration date still can't complete most online purchases without the security code.
Your card issuer checks the code against the one they have on file. If they match, the transaction moves forward. If they don't match, the transaction is blocked. This verification happens in seconds, behind the scenes, and you won't see it happen.
Some merchants, especially larger retailers, may not require the security code for every purchase. This is their choice, not a requirement. However, most online merchants do ask for it as a standard security measure.
How to protect your security code
Never share your security code with anyone except the merchant you're paying right now. Your bank, credit card company, or any legitimate business will never ask you to provide your security code over the phone, in an email, or through a text message. If someone asks for it in any of those ways, it's a scam.
Don't write your security code down or store it in your phone, email, or any digital file. The only place your security code should exist is on your physical card. If you're making a purchase and need to reference it, look at your card in the moment and enter it when ready.
If your card is lost or stolen, contact your card issuer right away. They will cancel the card and issue you a new one with a different security code. Until the new card arrives, you won't be able to make online or phone purchases, but your account will be protected from fraudulent charges.
What to do if you can't find your security code
If your card is damaged and the security code is worn off or illegible, contact your card issuer. They can read the code from their records and tell you what it is over the phone, after they verify your identity. You can also request a replacement card, which will have a new security code printed on it.
If you're trying to make a purchase and the merchant's website won't accept your security code, double-check that you're entering exactly three digits (or four for American Express) with no spaces or dashes. Make sure you're not accidentally including any letters or symbols. If the code still doesn't work, try refreshing the page or using a different browser.
If you've entered the code correctly multiple times and it's still being rejected, contact your card issuer. There may be a temporary issue with their verification system, or your card may have been flagged for fraud protection. The issuer can tell you whether the card is active and whether there are any blocks on online purchases.
Frequently Asked Questions
Is the security code the same as my PIN?
No. Your PIN is a number you create and use at ATMs and store terminals. Your security code is printed on your card and used for online and phone purchases. They are completely separate numbers, and you should never use your PIN as your security code or vice versa.
Can someone use my card if they only have the card number and expiration date?
They can try, but most online merchants will block the transaction if the security code is missing or incorrect. Without the physical card, a thief won't have the security code, so they can't complete most purchases. This is why the security code exists — to prevent exactly this scenario.
Will my security code change if I get a new card?
Yes. Each card has its own unique security code. If your card is replaced — whether because it expired, was damaged, or was lost — your new card will have a different security code. You'll need to update any stored payment information with the new code.
What should I do if I accidentally shared my security code with someone?
Contact your card issuer when ready and let them know. They can monitor your account for fraudulent activity and may issue you a replacement card with a new security code. Watch your statements closely for the next few months for any charges you don't recognize.
Do I need to memorize my security code?
No. You should never memorize or write down your security code. Only look at it when you're actively making a purchase, then enter it when ready. Keeping it only on the physical card is the safest approach.