What is an Account Number?

Felicia Dye

Numerous types of businesses manage their affairs by maintaining accounts. These include banks, credit card companies, and utility companies. The accounts that these businesses maintain are actually personalized files. To differentiate one file from another, each file is generally given an account number to identify it.

A checkbook with an account number on the bottom.
A checkbook with an account number on the bottom.

Account numbers are generally very useful and efficient file management tools. If a person goes to a bank to open a checking account, she should be given a checking account number. The purpose of this number is to manage transactions that pertain specifically to that customer’s transactions. If she needs to make a deposit, she will use her account number so the money can be credited to her and not to someone else. If she needs to withdraw funds, she will need her account number to ensure that she is not taking funds that do not belong to her.

The drive-thru at a bank. Customers can typically access their account through the drive-thru if they have the account number.
The drive-thru at a bank. Customers can typically access their account through the drive-thru if they have the account number.

Companies that manage customer files using account numbers often find it easiest to identify a customer file using this number. Names, for example, can create a problem because there may be many people with the same name. Account numbers, however, should be unique. Duplicate account numbers within a company are generally a mistake and can create numerous problems.

Account numbers can be completely numeric or they can be alpha numeric. Each company can generally decide how to format its account numbers. Businesses generally structure these numbers so an account number from another company cannot be mistaken for one of their own. For example, a bank should be able to readily identify that a mistake has been made if a customer uses her credit card account number.

Depending upon the type of account, there can be substantial risk involved in losing or sharing an account number. There are numerous reasons for this. A primary reason is that a customer’s file often contains confidential information such as her identity number, credit information, and her home address. Another reason that protection of account numbers is important is because if strangers obtain the numbers, they may gain access to a person’s resources, such as her finances.

Since many companies use account numbers, most companies try to make it convenient for clients to manage them. They do this by including each customer’s account number on statements and bills sent to them. The number is often printed on each check when a person has a checking account. Some businesses issue cards to each customer containing her unique number.

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Discussion Comments


I am in IT manager for a local bank. All of the databases that I helped to build for the bank use customer account numbers as a key identifier in storing customer information.

Besides a social security number, an account number is the only unique piece of information that a bank has to identify you with. Using this information makes data bases easy to build and manage. When a teller wants to bring up a customer's records, he or she can just enter in the customer's account number into the computer, press go, and everything will pop up automatically.

However, we do design our databases so that any identification information, such as a name, date of birth, or address, can be used to pull up a customer's data. But none of these data points are unique to any one individual.

If you want to make sure that your bank is doing business on your account and no one else's, then always have your account number with you when you make a transaction. Doing so will greatly reduce the chance that the bank makes mistakes in your records.


Is it just me, or is your bank account number not posted online? I can remember one time searching for at least 30 minutes on my bank's website for my account number. Perhaps they do not put it on there for your own security, because whenever I log into my account online, my bank account number is nowhere to be found.

I am just 20 years old. Growing up, I paid for everything with my debit card. I did not realize that both my account and routing numbers were printed on my checks. I do not use them very often, so I did not even noticed all those numbers at the bottom of them. I felt very silly when my mom pointed it out to me!

Thanks for writing this article. I learned a lot more about the importance of account numbers.


@SuperJD - Based on the way you describe your situation, I am pretty sure that somebody got a hold of your credit card account number. Like the article states, a lot of your personal information is tied to your account number, so the fact that yours might have been stolen is a very serious matter. The same thing happened to my sister, so I am pretty familiar with what to do in this situation.

If you have not done so already, immediately cancel your credit card. Just tell your agency that someone is making fraudulent purchases on your account, and they will close it right away.

Next, you should alert the three major credit bureau's that your account number has been stolen. They will put a fraud alert on your credit, so that your credit report is not destroyed by the person or people who might have stolen your information.

If you think that other information, like your date of birth or social security number was stolen, then you should contact the law enforcement authorities. They can assist you in the event of identity theft.

I would also suggest that you keep personal records of everything you buy with your credit card. If you do, then you will know right away if something is not right on your statement.

I hope this helps, and good luck!


Lately, I have been seeing weird things pop up on my credit card statements. In the past few months, there I have purchases on my statement that I do not remember making.

About two months ago, there were two or three line items on my statement that I did not recognize. I am a pretty absent minded person, so at first I thought that I had just bought something and forgot about it. But this month, there were at least five purchases charged to my account that I am pretty sure I did not make.

I think my credit card account number was stolen. What should I do about that?

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