How does SmartCalcs work?

TaxJar's SmartCalcs' '/v2/transactions/orders' endpoint takes the following information as input:

  • Location the order is shipped from
  • Location the order is shipped to
  • Order amount
  • Shipping amount
  • Product exemptions* (if applicable, please see below)

SmartCalcs then returns the amount of sales tax that should be withheld.

SmartCalcs determines the rate based on state, city, zip-code (as well as +4 information if it's included), and street address. The API takes into account whether or not the sourcing for this transaction in question is origin-based or destination-based, and whether or not shipping is taxable.

* SmartCalcs also supports item taxability. Certain products, including dietary supplements, clothes, and food are taxed at a reduced rate in some states and are sometimes even tax exempt. From clothing in New York to food in California, TaxJar's SmartCalcs Sales Tax API supports special sales tax circumstances for the products you sell. See our supported categories here: