What is a credit card number?

When shopping online or making a payment over the phone, some retailers may ask for your credit card number.

But what is this number – and what are all the other numbers on your card?

Credit Card Number

Generally when people use the term ‘credit card number’ they’re referring to the long number printed on the front of your credit card. This number is usually 16 digits long, but it can be up to 19 digits.

This number is created by your card provider, commonly Mastercard and Visa but not exclusively. All Mastercard credit cards will start with either 51, 52, 53, 54 or 55, but from 2017 new Mastercards will start with 22, 23, 24, 25, 26 or 27, for example.

The numbers are not selected at random; these figures are created to be unique to you. The number is produced using a mathematical system called the Luhn algorithm, invented by Hans Peter Luhn, an engineer working at IBM in 1954. This is now the internationally used standard for credit card numbers.

What are the other numbers on my credit card?

Sort Code and Account Number

Some cards will have a sort code and an account number. A sort code refers to the bank and branch where you opened your credit card. This is a six-digit number and takes the format of 00-00-01. The first two digits usually identify the bank and the remaining four digits are for internal use within the bank.

While the sort code refers to your bank and branch, your account number refers to your personal bank account. This is completely unique to you and your bank account, and your provider will not duplicate this number. An account number can be from 8 to 19 digits long.

Start and End Date

It is also common for some credit cards to have start and/or end dates printed on the cards.

The start date is the month and year you opened your credit card, for example 02/13 for February 2013. Typically, a credit card is issued for three years and then renewed. In this case the end date would be 03/16 – one month is added on to the end date to allow time to renew.

If your card has been renewed, your new card will have an amended start date, changed to the renewed date, i.e. 03/16 for March 2016. This is three years and one month after you first took out the credit card and with a new end date of 04/19.

Issue Number

There are some card providers that place an Issue Number on their cards, although not all card providers do this.

An issue number refers to the number of cards that have been issued to the card holder. For example, if you renew your card after it expires, the original card will have the number 1 as the issue number, and the newly renewed card will have number 2 as the issue number. This will also happen if you lose your card and request a new one.

Card Verification Value Number

Retailers sometimes ask for the CVV number on your credit card when paying for items over the phone or online. This is also sometimes referred to as CVV2.

CVV stands for ‘Card Verification Value’ and it is a security feature to prevent fraud. This number is most commonly found on the back of the card at the top right hand corner of your signature strip and is usually three digits long. There may be seven or so digits in total, but you're only likely to be asked for the last three.

We hope this has cleared up the mystery of what all those numbers on your credit card mean.