The IRS charges interest on late or unpaid taxes, regardless of cause. The period covered always begins with the original due date of the return, and ends with the receipt of payment by the IRS. You may incur interest expenses for late filing, or simply for making a mathematical error on your tax return.Generally, interest is charged on any unpaid tax from the original due date of the return until the date of payment. The interest rate on unpaid Federal tax is determined and posted every three months. It is the federal short–term interest rate plus 3 percent. Interest is compounded daily.
Interest must be paid in full before any abatement determination is made. Once you pay the bill, the “meter” stops running and additional interest charges will stop accruing.
