Understanding Social Security Numbers (SSN)

Key takeaways
* A Social Security number (SSN) is a unique nine-digit identifier issued by the Social Security Administration (SSA) to U.S. citizens, permanent residents, and certain temporary residents.
* SSNs are used to track earnings, determine Social Security and Medicare benefits, and serve as a primary identifier for tax, banking, and many government and financial services.
* Since 2011 SSNs are randomized; older patterns (area, group, serial) no longer indicate state of issuance, though their structure and legacy rules remain relevant to understanding the number format.
* SSNs are a prime target for identity theft — protect your SSN and act quickly if it is compromised.

What is an SSN?

A Social Security number is a nine-digit number issued by the SSA to identify individuals for Social Security and tax purposes. Initially created in the 1930s to track earnings and administer retirement and disability benefits, the SSN has since become a widely used identifier for banking, credit, government services, and employment.

SSN format and components (historical context)

The SSN is written as three groups of digits: AAA-GG-SSSS.
* Area number (AAA) — historically indicated the state or ZIP code on the application; assignments varied over time. Certain blocks were reserved for specific uses and some numbers (e.g., 666) are not assigned.
* Group number (GG) — a two-digit number used to organize issuance within an area; not directly sequential by individual.
* Serial number (SSSS) — a four-digit number from 0001 to 9999 (0000 is not used).

Since 2011, SSNs are assigned randomly, removing geographic significance of the first digits to reduce fraud and number-guessing.

Brief history

• 1935–36: Social Security Act established and the SSN introduced to track earnings for benefits.
• 1943: Federal agencies required to use SSNs for identification.
• 1962–1983: SSNs adopted for tax reporting and financial account identification.
• 1996–1999: Use on certain state records and licenses was rolled back to reduce exposure.
• 2011: SSA began randomizing SSN issuance.

Why SSNs matter

SSNs are central to:
* Recording earnings and calculating Social Security and Medicare benefits.
* Tax reporting (employers report wages to the IRS using SSNs).
* Opening bank and brokerage accounts; applying for loans, credit, and federal benefits.
* Obtaining a driver’s license, passport, or enrolling in Medicare in many cases.

Because the SSN connects financial, employment, and government records, it is essential for both access to services and long-term benefit calculations.

How to get or replace an SSN

1. Complete Form SS-5 (Application for a Social Security Card).
2. Provide original or certified documents proving identity, age, and U.S. citizenship or immigration status (the SS-5 lists acceptable documents).
3. Submit the form and documents to the SSA (in person or by mail, per SSA instructions).
4. Expect your card by mail once processing is complete (commonly two to four weeks; times may vary).

There is no fee to obtain or replace a Social Security card. Under limited circumstances, SSNs can be changed.

Protecting your SSN and dealing with identity theft

Risks
* SSNs are used to open credit, apply for benefits, and file taxes; possession of your SSN enables many forms of identity theft and fraud.

Preventive steps
* Share your SSN only when legally required.
* Keep the physical card in a safe place (do not routinely carry it).
* Use strong, unique passwords for online accounts that store sensitive information.

If your SSN is compromised
1. Contact the three major credit reporting agencies (Experian, TransUnion, Equifax) to place a fraud alert or credit freeze.
2. Notify the SSA about suspected fraudulent use of your SSN.
3. File a police report if your card was stolen or if identity theft has occurred.
4. Report identity theft to the relevant federal resources and agencies (for example, the federal identity-theft reporting and recovery site and the IRS for tax-related fraud).
5. Monitor credit reports, bank accounts, and IRS transcripts for unauthorized activity.

Common questions

Who is eligible for an SSN?
U.S. citizens, lawful permanent residents, and certain noncitizen residents (including many who work in the U.S.) are eligible. Non-working residents may also obtain SSNs for government and business purposes if they meet SSA requirements.

How long does it take to receive a card?
Typically two to four weeks after the SSA receives all required documentation; processing times can vary.

Can you change your SSN?
Changing an SSN is permitted only in limited circumstances (such as documented ongoing identity theft) and requires SSA approval.

What can someone do with my SSN?
With an SSN they can apply for credit, open accounts, file taxes, obtain medical services under your name, and access government benefits fraudulently.

Conclusion

An SSN is a vital identifier for earnings, taxes, benefits, and many financial transactions. Because of its central role and sensitivity, safeguard your number and card, provide it only when necessary, and act promptly if you suspect misuse.