Tax calculation services take the guesswork out of performing complex tax calculations by making it simple to add accurate tax information and pricing to a customers cart or at checkout in real-time. Calculating tax is complicated but tax calculation services take all variables into account, such as nexus locations, the category of goods for each cart item, the quantity of each cart item, the customers' shipping location and other tax requirements for individual jurisdictions at the country and state level. Tax calculation services may also provide seamless integrations with accounting software and streamline the tax filing process.