Income tax calculator software can be found online at the sites for Intuit and H&R Block. Intuit's TurboTax software is one of the most popular income tax calculators in North America.
Most customer service departments for income tax calculating software offer real time support for tax preparers, answering questions as they come up. The software works by taking the tax payer relevant forms and personal information, performing calculations and completing the appropriate forms. Using software can cut the time it takes to prepare taxes, but the closer the filer is to the deadline, the longer it may take to process the forms.