The leading gross-to-net calculation software for payroll. The Symmetry Tax Engine® (STE) is a powerful gross-to-net calculation engine to build or enhance a payroll platform, embed payroll into an existing application, and increase compliance and accuracy. The Symmetry Tax Engine® accounts for federal, state, and local payroll taxes — both withholding and latent employer taxes — for over 7,400 taxing jurisdictions and U.S. territories. Employer taxes and multi-state processing are accounted for as well. STE covers all 50 states, U.S. territories including Puerto Rico, and Canada. The Symmetry Tax Engine® was built by developers for developers, with more payroll integration flexibility for implementation and additional features, including options for a web API or on-premise SDK. With either version, you get the same great engine. The difference is where it’s installed and who does the testing and updating.