Calcoid

SSN Validator (Format Check)

Check whether a US Social Security Number follows the SSA's public format rules. Flags invalid area, group, and serial patterns, known placeholder numbers, and shows the pre-2011 state of issuance. Format check only, not a real-time SSA lookup.

Format check only.

This tool checks whether an SSN follows the public Social Security Administration formatting rules. It does NOT verify the number against SSA records, confirm it is assigned, or prove any identity. Never use it as proof of identity. Your input stays in your browser and is not sent anywhere.

SSN input

Enter 9 digits with or without dashes or spaces. Anything that isn't a digit is ignored.

SSA format rules

An SSN is 9 digits split as AAA-GG-SSSS:

  • Area (AAA) cannot be 000, 666, or 900-999.
  • Group (GG) cannot be 00.
  • Serial (SSSS) cannot be 0000.
  • 123-45-6789, 111-22-3333, and 219-09-9999 are documented placeholder numbers.
Result

Type an SSN above to see the format breakdown.

Frequently Asked Questions about the SSN Validator (Format Check)

What are the SSA's format rules for a valid Social Security Number?
An SSN has nine digits in AAA-GG-SSSS form. SSA rules exclude area numbers 000, 666, and 900 through 999, group number 00, and serial number 0000. A number that passes these format rules is only structurally possible; this calculator cannot establish that SSA issued it or that it belongs to a person.
What changed with SSA's 2011 randomization, and what was the pre-2011 system?
Before randomization, the area number generally related to the mailing address on the application, not necessarily birthplace or card-issuance state. SSA began random assignment on June 25, 2011 and removed geographic significance from new numbers. Any pre-2011 state label shown by this tool is historical context only.
What are known fake SSNs, and what can this tool infer?
078-05-1120 is the famous number printed on a sample card in Woolworth wallets, while 219-09-9999 appeared in an SSA pamphlet. Common placeholders such as 123-45-6789 may also be blocked by software. A denylist is not authoritative evidence of assignment, and this calculator cannot confirm whether any other structurally valid number was issued.
Why isn't this a real-time check against actual SSA records?
The Social Security Administration does not expose a public API to verify SSNs. The only authorized ways to confirm an SSN against SSA records are the Consent-Based Social Security Number Verification Service (CBSV) for businesses with signed consent, and the Social Security Number Verification Service (SSNVS) for employers verifying employee names against SSNs. Both require an SSA account, a signed agreement, and (for CBSV) a fee per query. This tool only checks format, the same way a credit-card form catches obvious typos with the Luhn algorithm before sending the number to the issuer.
What should I do to protect SSNs and avoid identity theft?
Do not enter a real SSN into a general-purpose format checker. Share it only with an authorized recipient through a verified secure process. If it was exposed, follow current guidance from the SSA and Federal Trade Commission, which may include reviewing records, reporting identity theft, and placing credit freezes or fraud alerts.

Related Calculators

More calculators in "Tech"

YouTube Money CalculatorText to Binary ConverterIBAN CalculatorEngine Displacement CalculatorAWS Lambda Cost CalculatorData Storage Converter
See all 98 calculators in "Tech"