What is a CVV Number?

A credit card CVV is a three- or four-digit code designed to prevent fraud. Normally found on the back or front of your credit card, CVV numbers are typically required for online purchases to verify that you're using a legitimate credit card in your possession. Find out how CVV numbers work to increase card security and how you can find your CVV on your credit card.

What Is CVV a Number?

CVV stands for card verification value but can serve as a catch-all term for the security code on credit cards. Each credit card company has its own name for it, such as CVV2, for card verification value code; CSC, for card security code; CVC or CVC2, for card verification code; or CID, for card identification number, according to card issuer Discover.

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The differences don't stop there, though. Visa, Mastercard and Discover use three-digit security codes, while the American Express security code is four digits.

Whatever its length or name, your credit card's CVV code is not part of your credit card number, debit card number, PIN or expiration date. These numbers are all separate from each other.

Where Can I Find My CVV Number?

Your card's CVV is printed on the card, though the location may vary. On Visa, Mastercard or Discover cards, the CVV is typically located on the back of the card, at the far-right side of the box where you are supposed to sign the card. The four-digit security code for an American Express card is usually on the front, above the credit card number. Some cards may have the security code in another location, such as on the back, below the credit card number.

If you want to find your CVV number without your card present, you may be out of luck. Typically, you can't access your CVV number online. However, there are exceptions. Some credit cards allow you to view your card information in a mobile app.

Contact the card issuer if you're having trouble locating the security code or if the code is worn down to the point that it's hard to read.

How Does My CVV Code Work?

Card security codes are a form of two-factor authentication. Two-factor authentication relies on two pieces of information -- such as a credit card number and a CVV -- to confirm you are the cardholder. The CVV verifies that the card is in your possession and, as a result, helps prevent fraud, says Monica Eaton-Cardone, co-founder and chief operating officer of the risk mitigation and chargeback management firm Chargebacks911.

"If a buyer can correctly enter the card's CVV during checkout, it's likely the person at least has the card in her physical possession," Eaton-Cardone says. "That makes it harder for criminals to use stolen cardholder information to make fraudulent purchases."

Entering the wrong code should result in a declined transaction, says Nicolas Beique, founder and CEO of payment processing platform Helcim.

Eaton-Cardone notes that even with regulations prohibiting merchants from storing your CVV information, transactions can still be authorized online without it. For instance, many subscription services only require the CVV be entered at sign-up; after that, additional purchases can be authorized without it.

"The CVV is sort of like a seatbelt for your credit card," Eaton-Cardone says. It's just one safety measure that, when used in conjunction with others, can offer layers of security for your credit card.

How Much Security Does a CVV Offer?

A CVV code is a layer of protection that makes fraud difficult but not impossible.

"There is a reduced chance that your account will be used to make unauthorized purchases when someone obtains your credit card number without the CVV code," says Bruce McClary, senior vice president of communications for the National Foundation for Credit Counseling. "You may still be vulnerable in situations where the card is used without your permission on a website that does not require the CVV code to be entered."

Cybercrimes present additional risks. Cyberthieves can employ software known as malware to steal security codes from retailers.

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Credit card CVV numbers are also susceptible to phishing attacks, where scammers use fraudulent emails or copycat websites to trick cardholders into sharing sensitive information, including security codes. A common scam is spoofed texts or phone calls that look like they are coming from your credit card company, asking for your CVV number to verify a recent purchase. If you receive a similar communication, ignore it and call your credit card issuer.

How Can I Protect My CVV?

To avoid becoming a victim of credit card fraud, here are four tips for safeguarding your credit card CVV number.

1. Don't post photos of your credit card, including the CVV, on Facebook, Twitter or other social media platforms.

2. Install antivirus software on your computer to shield credit card information, including the CVV number, from scammers when you're shopping online. Among Eaton-Cardone's recommendations are Webroot SecureAnywhere AntiVirus, Bitdefender Antivirus Plus, Kaspersky Anti-Virus, AVG AntiVirus, Avast Free Antivirus and Norton AntiVirus Plus.

3. Ignore unsolicited requests for sensitive credit card data, including your CVV code. Do not respond to or click on links in emails from unfamiliar sources.

4. Look for signs of security. Shop on secure websites equipped with secure sockets layer technology. SSL validates the identity of a website and encrypts transmitted data. An SSL site will have a padlock to the left of the URL, an https URL prefix rather than an http prefix and an SSL seal, usually in the footer, near the site's copyright information. Some sites have extended validation SSL certificates -- an SSL certificate requiring encryption and data integrity -- that feature green text or a green background in the address bar.

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Is it Safe to Give Out CVV Numbers?

Always closely guard your card's CVV code. If a thief has your credit card number, expiration date and CVV number, that is all the information the thief needs to make an online purchase.

While it is generally safe to give your CVV number to trusted merchants, it's not always necessary. If you're using a card in person, the CVV code typically isn't required. In general, providing a card security code when you're shopping online is safe, as long as you're making purchases from trusted websites. Typically, it's also OK to give a CVV number over the phone. Just make sure no one is eavesdropping and can hear the numbers.

One way some credit card issuers are trying to bypass the entire CVV issue is by supplying virtual credit cards with randomly generated account numbers for online purchases. Users of Citi's Virtual Account number service, available with select cards, can create temporary credit card numbers for one-time use instead of using their real credit card numbers. The 16-digit account number, including a security code and an expiration date, helps safeguard your online privacy.

Lance Cothern and Coryanne Hicks contributed to this article.