What is an online income tax calculator?

An online income tax calculator is a tool that helps taxpayers estimate their income tax refund or liability, says efile.com. The calculator is not meant to be a federal tax preparation tool. While the estimations are useful, they are not guaranteed to be accurate, notes 1040.com

To use the income tax calculator, users input information such as wages, number of dependents, tax deductions and tax credits, as stated by efile.com. According to a 2013 report by Forbes, the average tax refund is about $3,000, and 90 percent of tax returns are filed online. The Internal Revenue Service collects approximately 140 million tax returns each year.