If you’ve ever applied for a job, loan, or credit card, you’ve probably been asked for your Social Security number. In many ways, your Social Security number is as much a part of you as your date of birth—it follows you from birth to death and can serve as a key to your sensitive information.

It’s clear that having one is vital because it’s used in various ways. You probably even know the number by heart. But have you ever wondered what Social Security numbers mean?

In this guide, discover what a Social Security number is, how to decode the numbers, if they’re reused, and what your number says about you.

What is a Social Security number?

It seems everyone asks for your Social Security number (SSN) these days. So, what is it? An SSN is a unique identifier issued by the Social Security Administration (SSA).

The number was originally a way for the government to keep track of your earnings and the money you paid into the Social Security program. But now, you can use it in a variety of ways:

• Tax reporting 
• Help assure a person’s identity
• Open a bank account
• Apply for federal or private student loans
• Open a line of credit, home loan, or auto loan
• Apply for a job
• Qualify for government benefits
• Get a passport
• Get a driver’s license

Most people receive an SSN when they’re born. If you don’t have one, you can ask the SSA to issue one to you. The SSA can also give you a replacement card if yours was lost or damaged.

What do the numbers in your Social Security number mean?

The digits in your SSN have a unique configuration. What Social Security numbers mean isn’t a secret—but it isn’t very well known.   

According to the SSA, your nine-digit SSN is divided into three parts:

• The area number is the first set of three digits.
• The group number is the second set of two digits.
• The serial number is the third set of four digits.

The original intent was to limit the range of numbers based on specific criteria. For instance, the area number was assigned according to the state in which the SSN was issued.

But several changes have been made since the passage of the Social Security Act in 1935.

Area number

The area number is the first three digits of your SSN. When first issuing numbers, the area number indicated the location of the SSA office that assigned the number. In 1973, the SSA’s Baltimore office began supplying SSNs and used the applicant’s ZIP code to determine the area number.

The system changed again in 2011. What do the first 3 digits of your Social Security mean now? Nothing. SSNs are assigned using “randomization,” and the numbers are not tied to a specific location.

Group number

Group numbers are the two digits in the middle of your SSN. Your group number can range from 01 to 99. So, what do the middle numbers in Social Security mean?

In the early days, the group number was used to identify records. Because the SSA issued SSNs before the era of computers, program administrators used the middle two numbers to organize the records into sub-groups. 

Each group number pointed to a specific area of filing cabinets, making the records easier to manage.

Serial number

The last piece of the SSN puzzle is the serial number. The serial number is the last four digits of your SSN.

They can range from 0001 through 9999 and help to ensure your number is unique. 

How are Social Security numbers assigned?

How SSNs are assigned has changed throughout the years. Initially, the SSA used a system to issue numbers. For example, area numbers told the location where the card was given, and group numbers identified the filing cabinet where the record could be found.

The SSA transitioned to a new system of “randomization” on June 25, 2011. The change was “to help protect the integrity of the SSN,” according to the SSA.

Are Social Security numbers reused?

The SSA has issued over 453 million SSNs and supplies about 5.5 million new numbers per year. At that rate, you may think the SSA would run out of unique numbers to assign. 

However, the SSA does not reuse SSNs—not even after a person dies. Because of the switch to a randomized numbering system, the SSA reports having enough new numbers available for many future generations.

What does your Social Security number say about you?

Now that you know what Social Security numbers mean, what does your number say about you? Fortunately, not much.

Your area number may indicate the state from which your SSN was issued or the ZIP code you used to apply if the SSA issued your number before 2011. However, since the change to a randomized system in 2011, there’s no Social Security number decoder or way to decipher what the numbers mean.