Language Translation
  Close Menu

Streamlined Sales Tax

Streamlined Sales Tax graphic with text that reads "a simpler and more uniform sales and use tax system."

Streamlined Sales Tax (SST) is a program that simplifies the process of collecting sales and use tax on business operating in multiple states.

Indiana is one of 24 participating states that work to simplify tax laws, apply standard tax definitions, use common forms and procedures, and certify tax administration software, to ease tax collection in full member and associate member states.

If you have Indiana specific Streamlined Sales Tax questions, contact Indiana Department of Revenue (DOR) by email or call us at 317-615-2900.


All businesses wishing to become members of Streamlined Sales Tax must register at the following national registration site. Upon receipt of a national registration, DOR will send instructions, if any, for the business to register with the State of Indiana.

Indiana's Business Rules

The information below is for individuals or organizations that are developing retail sales tax calculation engines to participate in the Streamlined Sales Tax Project.

Associate Member States: There are two types of associate member states:

  1. A state may fully comply with the Streamlined Sales and Use Tax Agreement.
  2. A state may comply with the majority of the Streamlined Sales and Use Tax Agreement; however, some laws may not be compliant.

(Full) Member State: A state whose laws fully comply with the Streamlined Sales Tax Agreement.

Governing Board: The Governing Board is made up of representatives from all
full member states and associate member states.

Destination Sales Tax/Destination Sourcing: Sales tax is owed to the state where the product is delivered.

Certified Service Provider (CSP): The Governing Board certifies service providers to provide services for Model 1 sellers.

Certified Automated Software (CAS): The Governing Board approves and certifies software. Example: A company buys a certified software program to file a return. Certified software is referenced in Model 2.

Models: There are four models of sellers (1, 2, 3, and other). When businesses register they will choose their model (or filing method):

  • Model 1: Contracts with a Certified Service Provider.
  • Model 2: Business use Certified Software.
  • Model 3: Business creates an internal software program to file their return.*
  • Model 4 (Other): Business files return without using a CSP or any Certified Software.

*To register as a Model 3, the business must have sales revenue of more than $500 million annually and do business in at least five of the member states.

 Latest News

Click here to view more events

 Top FAQs