Social Security Number Formula

The Social Security Number (SSN) was crafted in 1936 in order to keep track of the earnings of U.S. workers so that their Social Security benefit entitlement could be calculated. The SSN has now expanded and is one of the most common number systems used. This is how the Social Security number system is broken down:

### -##- ###
Area Number Group Number Serial Number

The First Part – Area Number

Beginning in 1973, the first three digits of a Social Security Number were related to the zip code of the mailing address that is on the application. Before 1973, the numbers were assigned in field offices and was unique to each individual field office.

No legal Social Security numbers will start with:

  • 000
  • 800s
  • 900s
  • 666

This is an immediate indicator that a Social Security number is fake or written incorrectly.

Since these first numbers are related to the area and state where you filed the Social Security Number application, it sometimes refers to the state where you were born. We have put together a state and territory prefix that will tell you which state has which numbers.

This is not a reliable way to determine a Social Security number because there are no laws that says you must file in the state where you were born. The numbers are similar to how the U.S. has established zip codes. Lower numbers are typically found in New England and the Northeastern U.S. and rise as you move south and west.

Note that since 2011, this system has changed to a random numerical system that no longer ties to your geographical location. This was for identity protection.

The Second Part – Group Number

This part of a Social Security number is simply for the purpose of processing and filing for the SSA. There is no real significance to how this number is determined other than in a simply pattern. The numbers don’t simply start at 00 and go up. They actually start with odd numbers and then go to even numbers. A little trick to make it hard to track.

The Last Part – Serial Number

The last part of your Social Security number is the most complicated part. The serial section is a numerical number combination between 0001 and 9999, segmented within each Group number.

How Social Security Numbers Have Changed over Time

Today the SSN is 9 numbers long, but before the system was created in 1936, there were a few different options. There was the option of the 9-digit number we have today, an 8-digit number that consisted of a 5 digital serial number with a 3 digit geographic indicator, and a 7-digit version which had 4 digits and 3 alphabetic characters.

For those born in the last few years, Social Security Numbers have changed. In 2007, the Social Security Administration said that it was going to change the previous method for giving out Social Security Numbers and go to a random process. This change went into effect in 2011.

Now, there is no longer geographical significance to the first three digits, and now they have begun using numbers never used before, like 900s.

Getting A New Social Security Number

If you have a newborn child or are a new citizen to the United States, there is a process to get a new Social Security number. This process involves printing out for your new Social Security card which will contain your ID number. You can use this number to apply for bank accounts and for scholarships, and will be essential to establishing yourself as a citizen in the US.


How Is Your Social Security Number Determined?

If you were born before 2011, then the first part of your Social Security number is determined by where you were registered. The second part is a random sequence, and so is the last.

What Are The First 3 Digits Of My Social Security number?

The Social Security Prefix guide will help you determine the first three digits if you know where you were born. If you don’t know where you were born, you will be unable to figure out the first three digits.

Can I Figure Out My Social Security Number?

It’s impossible to figure out your Social Security number even if you know all of your personal information.

Elliot Marks

Elliot Marks

Author & Social Security Advisor

Elliot Marks has spent over 10 years providing clear and concise information to help Americans navigate the complex nuances of social security and many other government services in the United States. Elliot has a passion for helping those in need of these services to be able to find timely access to news and information that is relevant and helpful to their daily lives.