The IRS interest rate on underpayments is set quarterly. For the third quarter of 2020 (July 1 through September 30), the rate for an individual is 3%. Interest compounds daily. It’s wise to request an installment payment agreement to get outstanding taxes under control. Interest will continue to accrue on the balance, but eventually, the debt will be gone.
Items, such as interest, state and local income and sales taxes, charitable contributions, and medical deductions, claimed on Schedule A of Form 1040. Itemized deductions are subtracted from adjusted gross income to arrive at taxable income. The amount of itemized deductions is also subject to a reduction when adjusted gross income exceeds certain limits.