What is a tax interest calculator?

A tax interest calculator determines the amount of interest owed on taxes that are paid late, as seen on the New York State Department of Taxation and Finance website. Several state tax websites, including New York and Pennsylvania, provide tax interest calculators, as do third-party services.

The tax interest calculator on the New York State Department of Taxation website asks for the type of taxes that are owed, the due date of those taxes, and the date they are estimated to be paid. The calculator on IRSCalculator.com determines interest for federal taxes by asking for the tax filing year, the due date and the taxpayer type.