TIN format checker

Paste a TIN and find out whether it is even a possible SSN, ITIN or EIN before you send it to the IRS or chase the vendor. This checks structure only; it cannot tell you whether the number is issued or belongs to the name on the W-9.

TIN (with or without dashes)

Not sent anywhere. Clear the field when you're done.

Expected type

Enter nine digits.

What the checker looks at

Length and characters. Nine digits. Anything else is IRS TIN Matching code 1. Leading zeros matter: "012345678" is a valid format that spreadsheets silently turn into "12345678".
SSN structure. The area (first three digits) can't be 000, 666 or 900 to 999; the group (middle two) can't be 00; the serial (last four) can't be 0000. Since 2011 the SSA assigns numbers randomly, so nothing else about the area number tells you where or when it was issued.
ITIN structure. Nine digits beginning with 9, with a fourth-and-fifth-digit group in the ranges the IRS assigns to ITINs (50 to 65, 70 to 88, 90 to 92, 94 to 99). An ITIN holder is an individual; the W-9 should carry a person's name.
ATINs and IRSNs. A 9-series number whose group digits are 93 is an ATIN; group digits 89 are reserved for other programs (the IRSN table shows 89 is the Fresno campus range); and the campus codes 01 to 10, 17 to 19, 28, 29, 37 to 39, 49, 66 and 89 mark an IRSN, an internal IRS placeholder that is not a valid TIN. The checker names each separately.
Placeholders. Repeated digits (000000000, 111111111, 999999999), 123456789, the Woolworth number 078-05-1120, and the SSA advertising range 987-65-4320 to 4329 are flagged even though some pass the structural rules; the IRS rejects them and a real payee never has one.
EIN prefix. The first two digits of an EIN come from a fixed set of campus and internet-assignment prefixes. A prefix outside that set (for example 00, 07, 08, 09, 17, 18, 19, 28, 29, 49, 69, 70, 78, 79, 89, 96, 97) has never been issued.

The ITIN ranges come from the IRS's own manual for the ITIN unit: "The ITIN will be in the format of an SSN and begin with the number '9'. The fourth and fifth numbers will range from: 50-65, 70-88, 90-92, 94-99," and "'89' and '93' are NOT used as fourth and fifth numbers for ITINs but are reserved for other programs" (IRM 3.21.263.2(9)-(10), Aug. 28, 2025). A 93 in that position is an ATIN, an adoption taxpayer identification number for a child, not a payee's TIN (IRM 3.21.263.9.3.5(4)). Middle digits 01 to 10, 17 to 19, 28, 29, 37 to 39, 49, 66 and 89 are campus codes of an Internal Revenue Service Number, a temporary placeholder the IRS assigns internally, and the manual states that "An IRSN is not a valid TIN" (IRM 3.21.263.5.5, Jan. 1, 2015; 3.21.263.6.4.1 Reminder, Aug. 28, 2025). The checker reports these separately because a payee can read an IRSN off an IRS notice in good faith; it will not TIN-match and should not be accepted on a W-9. See ITINs on W-9s and 1099s.

Passing this check means the number could exist. Whether it does, and whether it goes with the name, is what IRS TIN matching answers.

🎮 Test yourself: Real or Fake TIN?, a 4-minute knowledge game.