What's the difference between a Visa card number and security code?

Your Visa card number and security code help verify the card’s authenticity. You need them, along with the card’s expiration date, to make purchases online or over the phone. Luckily, your Visa card number and security code are easy to distinguish once you know what you’re looking for.

How Visa card numbers and security codes work:

• Card number: A Visa credit card number can be 13-to-19 digits long. It’s usually printed right on the front of your card. But some cards have begun to put the number on the back as an extra security measure. Either way, you can’t miss it. Your card number is completely unique. It’s the primary piece of information merchants use to identify your account.
• Security code: A Visa card’s security code is a 3-digit number printed on the back, to the right of the signature box. It plays a big role in online and phone transactions, since you can’t just swipe, tap or insert your card. The code helps confirm that a card is legitimate. If someone just has your card number but not the security code, they can’t use it.
• Expiration date: The month and last two numbers of the year in which your Visa credit card expires are printed on the front of your card. It might say “08/24,” for example. It’s the date through which the card remains valid. In other words, your card will work through the last day of the month listed. This is the last big piece of information you’ll need to make purchases online or by phone.

When you swipe, tap or insert your card at a store, you won’t have to worry about your Visa card number and security code, as the computer system deals with them automatically. But it’s good to know where everything is when you need to make a purchase manually. For example, the security code for Visa, Mastercard and Discover is 3 digits on the back of your card. For American Express cards, it’s 4 digits on the front.

The card number is the big one on the front, and your security code is the 3-digit one on the back.