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.
Total business receipts reported on Schedule C or Schedule C-EZ before deducting adjustments for returns and allowances and cost of goods sold.