Penalties and interest apply to any deficient or delinquent payments. A penalty of 5 percent of the unpaid amount is added for each month (or part of the month) that a payment is delinquent or deficient, to a maximum of 25 percent. Interest is computed at the current rate of interest.
The interest rate on all taxes collected or administered by the Department of Revenue is 8%, effective July 1, 2017 through June 30, 2018. The interest rate for installment payments is 11%, effective July 1, 2017 through June 30, 2018.
The interest rates effective for July 1, 2016 through June 30, 2017 were 7.5% and 10.5%, respectively.