SSN validator: check the format of a Social Security number
This SSN validator checks whether a US Social Security number has a valid structure. It tests the rules the Social Security Administration (SSA) publishes: nine digits; an area number (the first three digits) that is not 000, not 666 and not in the 900s; a group number (the middle two digits) that is not 00; and a serial number (the last four digits) that is not 0000. Type or paste a number and you see which rule it passes or fails.
It is a format check, not an SSN verification. It cannot tell you whether a number was issued, whether it is active or whose it is, and it does not look anything up. The digits stay in your browser, are never sent anywhere or stored, and are hidden on screen by default. Developers and testers use it to check input validation rules, and form builders to see why a number is rejected.
How to use the SSN Format Validator (US)
- Type or paste the number. Spaces and hyphens are fine: 123-45-6789, 123 45 6789 and 123456789 all work.
- Leave Hide the digits on screen ticked if someone could see your screen, or untick it to see the three parts.
- Read the verdict and the list of rules, each marked Pass or Fail.
- Copy the result if you need it; the copied text never contains the number.
SSN Format Validator (US) features
SSA structural rules
Area, group and serial rules checked one by one, with the failing rule named.
Private by design
The check runs in your browser; nothing is stored or sent, and the digits can be hidden on screen.
Flexible input
Digits only, hyphens or spaces, with a clear message for bad layouts, wrong length and letters.
Honest about limits
Notes explain what a pass does not prove, and flag well-known sample numbers and the ITIN range.
The SSN format rules
An SSN is nine digits written as AAA-GG-SSSS. Since the SSA moved to random assignment on 25 June 2011, there is no geographic meaning in the first digits, but some values are still never assigned: an area number of 000, 666 or 900–999, a group number of 00, and a serial number of 0000. Any number containing one of them is invalid.
Numbers in the 900s are used by the IRS for Individual Taxpayer Identification Numbers (ITINs), which look similar but are not Social Security numbers. A few numbers that follow all the rules, such as sample numbers printed in public examples, are well known to be dummy values and are flagged.
| Part | Digits | Not allowed |
|---|---|---|
| Area number | 1–3 | 000, 666, 900–999 |
| Group number | 4–5 | 00 |
| Serial number | 6–9 | 0000 |
What a pass does not mean, and privacy
- A valid format does not mean the number was issued. Many format-valid numbers have never been issued, and a made-up number can pass.
- To verify a number for employment, use the SSA’s own verification service through your payroll provider or employer account. Do not use a random website for that.
- Do not type a real number into any page you do not trust. This tool does not transmit it, but the safest habit is to test with sample numbers whenever you can.
- For other ID formats, see the PAN card validator (India) and the GSTIN validator.
SSN Format Validator (US) FAQ
What makes an SSN invalid?
An area number of 000, 666 or 900–999, a group number of 00, a serial number of 0000, or a number that is not nine digits.
Can this tool verify that an SSN is real?
No. It checks the format only. Only the Social Security Administration can confirm that a number was issued and matches a name.
Is my number sent or stored?
No. The check runs in your browser and nothing is transmitted or saved. The digits are also hidden on screen by default.
Why does a number starting with 9 fail?
Numbers beginning with 9 are not assigned as Social Security numbers. The IRS uses that range for ITINs.
Do I have to type the hyphens?
No. 123456789, 123-45-6789 and 123 45 6789 are all accepted. Mixed or misplaced separators are flagged.
Why is 078-05-1120 flagged?
It passes the rules, but it is a famous sample number that appeared in public examples, so it is not a real person’s number to rely on.