Social Security Numbers began in 1936 as a way to track earnings for the new Social Security program

The first Social Security Number was issued on November 24, 1936, to a woman in New Hampshire. The program itself had just been signed into law by President Franklin D. Roosevelt in August 1935 as part of the New Deal response to the Great Depression. The government needed a way to keep records of how much each worker earned so it could calculate retirement benefits later.

Initially, Social Security Numbers were meant only for that one purpose — tracking wages for the Social Security retirement system. The nine-digit format was chosen because it could create enough unique combinations to cover the entire U.S. population. By the end of 1936, about 30 million numbers had been issued. Today, nearly every American has one, and the number has become far more than a retirement tracking tool.

Key Takeaways

  • Social Security Numbers were created in 1936 specifically to track earnings for the new Social Security retirement program.
  • The nine-digit format was designed to provide enough unique numbers for the entire U.S. population.
  • Over time, the number became used for tax filing, bank accounts, credit reports, and many other purposes beyond its original intent.
  • The structure of the number — area number, group number, serial number — was originally geographic but is now assigned randomly.

How the numbering system was originally structured

The nine-digit Social Security Number is divided into three parts: the area number (first three digits), the group number (middle two digits), and the serial number (last four digits). When the system started, the area number was based on geography — the state where a person applied for the number. This made it possible to guess roughly where someone was from by looking at their number.

This geographic structure created problems. It made Social Security Numbers easier to forge, and it revealed personal information just from the number itself. In 2011, the Social Security Administration stopped using geography to assign area numbers. Now the numbers are assigned randomly, which makes them harder to predict and less revealing of where someone lived when they got the number.

Why Social Security Numbers expanded beyond retirement tracking

For the first few decades, Social Security Numbers were used almost exclusively for the Social Security program. But as the federal government grew and needed ways to track taxpayers, the number became more useful. The Internal Revenue Service began using it for tax filing in the 1960s. Banks and credit companies started using it to identify borrowers and build credit reports.

By the 1970s and 1980s, Social Security Numbers had become the standard identifier for almost any financial transaction. Employers used them to report wages. Schools used them to track students. The number was never designed to be a universal identifier, but it became one anyway because it was already in place and widely known. Today, you typically need a Social Security Number to open a bank account, get a credit card, take out a loan, or file taxes — none of which were part of the original 1936 plan.

When children started receiving numbers at birth

For most of Social Security's history, people only got a number when they applied for it, usually as a teenager or adult entering the workforce. Children did not automatically receive numbers. This changed gradually through the 1980s and 1990s as the IRS and other agencies found it useful to have numbers for dependents.

By 1989, the IRS required parents to provide a Social Security Number for any child claimed as a dependent on tax returns. This meant most children got numbers by age five or six. Today, it is common for newborns to receive a number within weeks of birth, though it is not legally required at birth. Parents can choose to apply for one later, but most do so early because of tax and financial account requirements.

How the Social Security Administration manages the number system today

The Social Security Administration (SSA) is the federal agency responsible for issuing and managing Social Security Numbers. It issues roughly 5.5 million new numbers each year. The SSA maintains records of who holds each number and tracks when numbers are reported as stolen or misused.

Because Social Security Numbers are now used for so many purposes — credit, banking, employment, government benefits, medical records — they have become valuable targets for identity theft. The SSA does not prevent you from sharing your number, but it recommends limiting who you give it to. You do not need to carry your Social Security card with you, and many experts suggest keeping it in a safe place at home instead.

The difference between a Social Security Number and an Individual Taxpayer Identification Number

Not everyone in the United States has a Social Security Number. Non-citizens who are not authorized to work but need to file taxes can get an Individual Taxpayer Identification Number (ITIN) instead. ITINs are issued by the IRS and follow a similar nine-digit format, but they start with the number 9 and are used only for tax purposes.

An ITIN does not give someone work authorization or Social Security benefits. It is purely a tax identification tool. Some people hold both an ITIN and later obtain a Social Security Number if their immigration status changes. The two numbers serve different purposes and are managed by different agencies — the IRS for ITINs and the SSA for Social Security Numbers.

Frequently Asked Questions

Can I get a new Social Security Number if I want one?

The Social Security Administration will issue a new number only in specific circumstances, such as if your number has been stolen and used for fraud, or if you are experiencing harassment or abuse. You cannot simply request a new number because you want one. If you believe your number has been misused, you can contact the SSA directly to discuss your situation.

Why do babies need Social Security Numbers now when they didn't before?

The IRS began requiring numbers for dependent children on tax returns in 1989 to prevent tax fraud and to track child support. Before that, parents could claim children without providing identifying information. Now the requirement is standard, and most parents apply for a number for their newborn within the first few months of life.

Is my Social Security Number the same as my tax ID?

Your Social Security Number functions as your tax identification number for most purposes. However, businesses and self-employed people can also get an Employer Identification Number (EIN) from the IRS, which serves as a separate tax ID. Non-citizens may use an ITIN instead of a Social Security Number for taxes. The number you use depends on your employment status and immigration status.

What should I do if I lose my Social Security card?

You can request a replacement card from the Social Security Administration in person at a local office, by mail, or through their website. You do not need the card itself to use your number — the card is just proof of the number. Many people keep their card at home rather than carrying it, since you rarely need to show the physical card.