The data file is fixed-length ASCII
in the following format:

FIELD  POS LENGTH

ZIP     1    5    - unique key1 for this record, 5 digit ZIP code
FIPS    6    3    - standardized county number
ST      9    2    - state abbreviation
COUNTY  11   25   - county name
CITY    36   28   - city name
ST_ST   64   8    - state Sales Tax rate
CO_ST   72   8    - county sales tax rate
CI_ST   80   8    - city sales tax rate
ST_UT   88   8    - state Use Tax rate
CO_UT   96   8    - county use tax rate
CI_UT   104  8    - city use tax rate
CRLF    112  2    - carriage return/line feed

There are two files included with each monthly or quarterly update: STCZIP.txt contains exactly one record per ZIP code, as defined by the United States Postal Service.  In instances where there may be multiple tax authorities crossing over into the boundary of a ZIP code, the tax rate that applies to the majority within that ZIP code will be specified in this record.

¹The second file, STCZIP2.txt, can contain more than one record per ZIP code which may be differentiated by city or county names; there may also legitimately be more than one record for exactly the same city and county which may need to be manually chosen between, or simply use the first listed which matches the one record provided in STCZIP.txt.

The Sales Tax rate should be used when the merchant meets the legal definition of "nexus" of having a business presence in the location receiving the product or service, generally determined on a state by state basis.

The Use Tax rate should be used when the merchant does not meet the legal definition of "nexus" of having a business presence in the location receiving the product or service.  Use Taxes are the responsibility of the receiver to report and are not the responsibility of the merchant to report.

In instances where there may be additional regional taxes, they would be included in the County CO_ST and/or CO_UT fields.