Your Social Security number contains exactly 9 digits, divided into three sections

A Social Security number (SSN) is always written as XXX-XX-XXXX: three digits, then two digits, then four digits. The Social Security Administration assigns this number to you, and it stays the same for life. Each section of the number carries different information about when and where it was issued.

The number itself does not encode your birth date, state of residence, or other personal details the way some people assume. Instead, the three sections tell the SSA's internal filing system where your record is stored and when it was created. Understanding what each part represents can help you spot errors on your own records and understand why the SSA organizes numbers the way it does.

Key Takeaways

  • A Social Security number has 9 digits split into three parts: a 3-digit area number, a 2-digit group number, and a 4-digit serial number.
  • The area number (first three digits) originally corresponded to the state where you applied for the number, though this connection no longer holds for numbers issued after 2011.
  • The group number (middle two digits) and serial number (last four digits) are assigned sequentially by the SSA and do not encode personal information.
  • Certain number combinations are never issued — for example, 000, 666, or 900–999 in the area section, or 0000 in the serial section.
  • You can verify your own SSN on your Social Security statement or tax documents, but the SSA does not issue numbers over the phone or by mail on request.

The first three digits: area number

The first three digits of your SSN are called the area number. Before 2011, this number indicated the state where you applied for your Social Security card. Someone born in California who applied there would receive an area number in the California range; someone who applied in Texas would get a Texas area number.

This geographic link no longer applies to numbers issued after November 2010. The SSA switched to randomized assignment, meaning new area numbers are no longer tied to location. However, millions of people still hold SSNs issued under the old system, so the area number on an older card may still reflect where that person applied decades ago — not necessarily where they live now or were born.

The SSA never issues area numbers of 000, 666, or 900 through 999. These ranges are reserved and will never appear on a valid Social Security card.

The middle two digits: group number

The second section of your SSN — the two digits in the middle — is the group number. This number does not represent anything about you personally. Instead, it is part of the SSA's filing system for organizing records within each area number range.

Group numbers run from 01 to 65 and are assigned in a specific order as the SSA issues new numbers. The SSA does not skip around randomly; it issues them in sequence. This means the group number can sometimes tell you roughly when a number was issued relative to others in the same area, but it carries no information about the person holding the number.

The last four digits: serial number

The final four digits of your SSN are the serial number. Like the group number, this is purely an organizational tool. Serial numbers run from 0001 to 9999 within each group, and they are assigned in order as new numbers are created.

The SSA never issues a serial number of 0000. This restriction exists to prevent confusion in record-keeping systems. Beyond that, the serial number itself does not encode information about you — it is simply the next available number in the sequence when your SSN was assigned.

Why certain number combinations are never used

The SSA maintains a list of number combinations that are never issued, even though they fall within the valid range. Beyond the area numbers 000, 666, and 900–999, and the serial number 0000, there are no other blanket restrictions. However, the SSA has occasionally withheld specific numbers for administrative reasons or to prevent confusion.

These restrictions exist mainly to keep the numbering system organized and to prevent errors in record-keeping. A number like 000-00-0000 would be too easy to confuse with a blank field in a database. The restrictions do not reflect any superstition or hidden meaning — they are practical choices made by the agency that manages the system.

How to find your own Social Security number

You can find your SSN on several documents you likely already have. Your Social Security statement (which you can view online at ssa.gov if you create an account) displays your number. Your tax return, W-2 form, or 1099 form will also show it. Your Social Security card itself, of course, has the number printed on it.

If you have lost your card or cannot locate your number, you will need to contact the Social Security Administration directly. You can visit a local Social Security office in person, call 1-800-772-1213, or create an account on ssa.gov to view your statement online. The SSA does not issue numbers by mail or phone on request — you must either visit in person or use the online portal.

What the number structure does not tell you

Many myths circulate about what a Social Security number reveals. Your SSN does not encode your birth date, race, gender, or any other personal characteristic. It does not indicate your credit score, criminal history, or immigration status. It is simply an identifier that the SSA uses to track your earnings record and benefits.

The only information genuinely contained in the number structure is the area (which may or may not reflect where you applied, depending on when you received it) and the sequence in which it was issued relative to other numbers in that area. Everything else about you — your age, location, income, and life circumstances — is stored in a separate database linked to your number, not encoded within the digits themselves.

Frequently Asked Questions

Can I tell where someone was born by looking at their Social Security number?

Not reliably. If the number was issued before 2011, the area number (first three digits) indicates the state where that person applied for their card, not necessarily where they were born. For numbers issued after 2011, the area number is randomized and has no geographic meaning. You cannot determine birth location from an SSN alone.

What does it mean if someone's Social Security number starts with 666?

A number starting with 666 is not valid. The SSA never issues area numbers of 666, so if you see this, the number is either fake or has been altered. Valid area numbers range from 001 to 665, and 667 to 899.

Can I change my Social Security number?

Yes, but only in specific circumstances. The SSA will issue a new number if you can show that your current number has been misused, that you are a victim of identity theft, or that you have religious or cultural objections to your number. You cannot change it simply because you dislike it or want a "luckier" number. Changing your SSN requires visiting a Social Security office with documentation of your reason.

Does the order of digits in a Social Security number matter?

Yes. The SSA assigns the three sections in a specific order: area, then group, then serial. Rearranging the digits creates a different (and likely invalid) number. The structure matters for the SSA's record-keeping system, even though it does not encode personal information about you.

Why does the SSA use 9 digits instead of more or fewer?

The SSA chose 9 digits when the system was created in 1936 because it provided enough combinations to issue unique numbers to the entire U.S. population without running out. With 9 digits, there are roughly 660 million possible combinations (excluding the restricted ranges). As the population has grown, the SSA has had to manage the pool carefully, but 9 digits has remained sufficient.