TIN format checker for 1099 vendor lists
A wrong TIN is the most common reason a 1099 comes back with a notice. Paste your list, one vendor per line, to find numbers that cannot exist before the IRS finds them.
Runs only in this browser tab. Nothing you type is sent anywhere.
What the checker looks for
- EINs with a prefix the IRS never assigns. The first two digits must be on the IRS list of valid EIN prefixes. No EIN starts with 00, 07, 08, 09, 17, 18, 19, 28, 29, 49, 69, 70, 78, 79, 89, 96 or 97.
- SSNs that cannot exist. No SSN starts with 000, 666 or 9, has 00 in the middle or ends in 0000. Numbers that start with 9 are ITINs.
- Excel damage. A TIN shown as 1.23457E+08 has lost digits. An 8-digit number usually lost its leading zero.
- Placeholders and masks. 123-45-6789, 111-11-1111 or XXX-XX-1234 are not real TINs.
- Duplicates. The same TIN on two lines can mean a duplicate vendor or a copy-paste error.
What it cannot check
A number can have a valid format and still belong to someone else. Only the IRS can confirm that a name and TIN match, through its free TIN Matching program in e-Services. Mismatches show up after filing as business rules SHAREDIRFORM014 and 015. See IRIS error codes.
The IRIS CSV tool runs the same checks on every row of your 1099 file, and the name control generator shows how the IRS matches names.
Frequently asked questions
Can this tell me if an EIN is real?
No. It tells you whether the format is possible. Use IRS TIN Matching to confirm a name and TIN pair.
Why does an EIN starting with 07 fail?
The IRS does not assign EINs with that prefix. It is usually a typo or two numbers mixed up.
Is my list uploaded?
No. The check runs in your browser and nothing is sent.
Sources
- IRS: How EINs are assigned and valid EIN prefixes
- IRS Publication 1099 (2026), General Instructions for Certain Information Returns
Last reviewed November 1, 2026.