What Is a CVV Number?

CVV numbers protect you. They provide an extra layer of security against someone taking your credit card number and using it in unauthorized ways. For example, retailers can store customers’ credit card numbers to make future purchases easier, but they can’t store CVV numbers after purchase or transaction authorization.³ If a website or merchant asks you for your CVV number, they’re taking an extra step to confirm you physically have access to the card and aren’t using a number stolen from a data breach or a photo of the card — assuming the credit card number and CVV number are on opposite sides of the card.

This is why you might be asked to supply a CVV number when using a new shipping address, even if you’re using a saved card number. After all, stolen credit card numbers aren’t typically used to send purchases to the rightful owner of that credit card, so an unfamiliar address is more likely to trigger a request for additional verification.⁴

Though they play an important role in keeping your transactions secure, CVV numbers are only one component of card security: They’re merely a way to verify the purchaser has physical access to the card. Therefore, they’re primarily important in transactions that take place online and over the phone, not in person. For added in-person security, cards rely on signatures, magnetic strips, and EMV chips. For more on how credit cards work, check out “How Do Credit Cards Work? Demystifying Credit Art & Science.”

Nor do CVV numbers protect you against phishing scams in which someone tries to trick you into giving away your card number and card security code. The best way to protect your number is to disclose it only to people and businesses you trust — and only for transactions that you initiate. If you think your card number or CVV code has been compromised in some way, contact your card issuer immediately. They can get you a replacement with a new number and CVV code, if necessary.

Finally, checking CVV numbers is primarily a step merchants can take to protect transactions from fraud. But retailers aren’t required to check CVV numbers, even if all their business is online — and some may never check at all.⁵ As a shopper, it’s important to practice good credit card security practices, like only shopping on websites with URLs that include “HTTPS” and never giving out your CVV or card information in response to an email or phone call.

CVV numbers are a relatively recent innovation created in large part to help make online shopping more secure. The rise in online shopping was likely the single biggest driver in adoption – especially for customers who had their card access interrupted anytime its authenticity was mistakenly called into question. By adding another means of authentication, CVV numbers made online credit card transactions more reliable and convenient.