SSN Validator
Validate US Social Security Number (SSN) format. Check if a 9-digit number follows SSN rules and patterns.
SECURITY WARNING
NEVER enter your real Social Security Number on any website unless absolutely necessary. This validator is for educational purposes and format checking only. All validation happens in your browser—we do not store or transmit any data. However, SSNs are highly sensitive and should be protected.
Enter Social Security Number
Format: XXX-XX-XXXX (dashes are automatically added)
For Testing Only
DO NOT use real SSNs. The SSA provides test numbers for software development:
- • Test Range: 987-65-4320 to 987-65-4329
- • These are designated for testing purposes only
- • Never valid for actual identification
SSN Format Rules
Social Security Numbers are 9-digit numbers issued by the US Social Security Administration. They follow specific format rules to prevent duplication and identify invalid numbers.
Structure (XXX-XX-XXXX):
- Area Number (XXX): First 3 digits - geographic or randomized (after 2011)
- Group Number (XX): Middle 2 digits - used for administrative purposes
- Serial Number (XXXX): Last 4 digits - unique identifier
Invalid SSN Patterns:
| Rule | Invalid value | Example |
|---|---|---|
| Area number | 000, 666, 900-999 | 000-12-3456, 666-12-3456, 950-12-3456 |
| Group number | 00 | 123-00-4567 |
| Serial number | 0000 | 123-45-0000 |
| All identical digits | repeated digit | 111-11-1111 |
| SSA advertising range | 987-65-4320 to 4329 | 987-65-4321 |
| Famous published numbers | permanently void | 078-05-1120, 219-09-9999 |
How an SSN is structured
A Social Security Number is nine digits in the form AAA-GG-SSSS. Each segment has its own rules, and this validator rejects any combination that the SSA could never issue:
| Segment | Digits | Rules |
|---|---|---|
| Area number | First 3 | Geographic before 2011, randomized since; never 000, 666 or 900–999 |
| Group number | Middle 2 | Administrative grouping; never 00 |
| Serial number | Last 4 | Unique within the group; never 0000 |
Since June 2011 the SSA issues area numbers randomly, so an SSN no longer reveals where someone was born or lived.
Frequently Asked Questions
Does this verify that an SSN is actually issued?
No. This validator only checks that the nine digits follow the SSA’s structural rules — valid area, group and serial ranges. It cannot confirm whether an SSN is registered, active, or belongs to a specific person; only the Social Security Administration can do that, and only through authorized channels.
Is it safe to use this validator?
The check runs entirely in your browser — nothing you type is sent to or stored on a server. That said, you should never enter a real SSN online except on official government or verified employer portals over HTTPS. For testing, use the SSA’s reserved test range (987-65-4320 to 987-65-4329) instead of a real number.
How is a Social Security Number structured?
An SSN is nine digits written as AAA-GG-SSSS: a three-digit area number, a two-digit group number, and a four-digit serial number. Since the SSA switched to randomized issuance in June 2011, the area number no longer maps to a geographic state — but the structural rules (no 000, 666 or 900–999 area; no 00 group; no 0000 serial) still apply.
Which SSNs are always invalid?
Several ranges can never be issued: an area number of 000, 666, or anything from 900 to 999; a group number of 00; or a serial number of 0000. A few numbers are also permanently void because they leaked into advertising — most famously 078-05-1120, printed on sample cards in the 1930s. This validator rejects all of these.
When would I need to validate an SSN format?
Format validation is built into HR onboarding, payroll, tax-prep and identity-verification systems to catch data-entry mistakes before a record is submitted. It is a first-pass sanity check, not proof of identity — and during software development you should always use the SSA’s reserved test numbers.
Is a CPN a valid Social Security Number?
No. A "CPN" (Credit Privacy Number) is not issued by the Social Security Administration and is not a valid SSN. CPNs are marketed as a way to hide bad credit, but using one in place of your SSN to apply for credit or employment is illegal and can amount to fraud. This tool only checks SSN format and does not generate or validate CPNs.
What are the numbers 987-65-4320 to 987-65-4329?
That block is reserved by the Social Security Administration for use in advertisements and software testing. The numbers look like real SSNs but have never been issued to anyone, which makes them safe to use as placeholders or test data. Because their area number (987) falls in the invalid 900-999 range, this validator correctly flags them as not real SSNs.
How do I know if a Social Security Number is valid?
Enter the nine digits above and the tool checks them against the SSA structural rules: the area number cannot be 000, 666 or 900-999, the group number cannot be 00, and the serial number cannot be 0000. If all three segments are in range it shows "Valid SSN format". Remember this only confirms the format is plausible - it cannot tell you whether the number was actually issued or who it belongs to.
Last updated June 10, 2026. SSN rules follow the US Social Security Administration; this tool checks format only and cannot confirm a real person’s number.