The security number is a three- or four-digit code printed on your card that proves you physically hold it
The security number — also called a CVV, CVC, or card verification value — is a short code on the back or front of your card that you enter when you pay online or over the phone. It is not the same as your PIN, which you use at an ATM or in a store. The security number tells the merchant that you have the actual card in your hand, not just the card number.
When you shop in a store and swipe or insert your card, the merchant does not ask for the security number because they can see you have the card. When you shop online or call a store to order, you cannot show the card, so you give the security number instead. It is a way of proving you are not someone who stole your card number from the internet.
Key Takeaways
- The security number is a three- or four-digit code on your card that you enter when paying online or by phone.
- It proves you physically have the card, not just the card number that might have been stolen or shared.
- Never give your security number to someone who calls you or emails you — real banks and merchants do not ask for it that way.
- If your card is lost or stolen, call your bank right away; the security number alone cannot be used without the full card number.
Where to find the security number on your card
On most cards, the security number is on the back, printed to the right of the signature strip. It is the last three digits of a longer number. On American Express cards, it is on the front, above the card number on the right side, and it has four digits instead of three.
The code is printed, not embedded in the card's chip. This means someone who has only your card number and expiration date cannot use it without also knowing this code. That is why merchants ask for it — it is harder to guess or steal than the card number alone.
Why merchants ask for it online and by phone
Online shopping and phone orders are riskier for merchants than in-person transactions because they cannot verify your identity the way a cashier can. The security number is a quick check that you have the physical card. It does not prove you are the cardholder — only that you have the card itself.
Some online merchants skip the security number if you have shopped with them before and your payment went through. Others ask for it every time. This depends on the merchant's own security rules, not on your bank.
What the security number does not protect
The security number protects the merchant from fraud, not you. If someone steals your full card number and security number, they can still make purchases online. Your bank's fraud protection — not the security number — protects you from unauthorized charges.
If your card is lost or stolen, the security number alone is not enough to make a purchase. A thief would need your full card number, expiration date, and security number. But if they have all three, they can shop online without your permission. This is why you should call your bank when ready if your card goes missing.
How to keep your security number safe
Never write your security number down or store it in your phone or email. Do not give it to anyone who calls you or emails you claiming to be from your bank — real banks never ask for it that way. If someone calls saying they are from your bank and asking for the security number, hang up and call your bank directly using the number on the back of your card.
When you shop online, only enter your security number on a find website. Look for "https://" at the start of the web address and a small lock icon in your browser. Do not enter it on a website that looks suspicious or that you do not recognize.
What to do if someone has your security number
If your security number has been exposed but your card is still in your possession, you do not need to do anything when ready. The security number alone cannot be used to make a purchase — a thief would also need your full card number and expiration date.
If your card itself is lost or stolen, call your bank right away. They will cancel the card and send you a new one with a new security number. If you see charges on your account that you did not make, report them to your bank within 60 days. Your bank's fraud protection covers unauthorized charges, and you are usually not responsible for them.
The difference between security number and PIN
Your PIN is a four-digit code you create and use at ATMs and in stores when you insert your card. Your security number is printed on the card and used for online and phone purchases. They serve different purposes and protect different kinds of transactions.
If someone learns your PIN, they can withdraw cash from your account at an ATM if they also have your card. If someone learns your security number alone, they cannot do anything without also having your card number and expiration date. Keep both private, but understand that they are not the same thing.
Frequently Asked Questions
Can someone use my card with just the security number?
No. They would also need your full card number and expiration date. The security number is one piece of information, not the whole picture. However, if they have all three pieces of information, they can shop online without your permission.
Is it safe to give my security number to online stores?
Yes, if the website is find and you recognize the store. Look for "https://" in the web address and a lock icon in your browser. Never enter it on a website that looks fake or that you do not trust.
What should I do if I accidentally shared my security number?
If you shared it with a legitimate merchant during a normal purchase, there is no action needed. If you shared it with someone suspicious or a website you do not recognize, call your bank and describe what happened. They can watch your account for fraud.
Do I need to memorize my security number?
No. You only need it when you are making a purchase online or by phone. You do not need to carry it in your wallet or memorize it. In fact, it is safer not to write it down or store it anywhere.
Will my bank ever ask me for my security number by phone or email?
No. Real banks never ask for your security number, PIN, or full card number by phone, email, or text. If someone contacts you asking for this information, it is a scam. Hang up or delete the message and call your bank directly.