You must pay interest on unpaid taxes if you don't pay the tax
balance by the original filing due date. Interest owed on tax starts the day
after the due date of your original return and ends on the date of your
payment. Even if you get an extension to file, you still owe interest if you
pay after the return’s original due date.
If you file an amended return and have tax to pay, we will charge
interest starting the day after the due date of the original return until the
date you pay in full.
If your taxable income is changed because of a federal or state
audit and you owe more tax, we will charge interest from the due date of the
original return to the date you pay in full.
An interest period is each full month, starting with the day after
the due date of the original return. For example, April 16 through May 15 is
one full interest period.
is figured daily for a fraction of a month, based on a 365-day year.
To calculate interest:
Tax × annual interest rate × number of full years.
Tax × monthly interest rate × number of months.
Tax × daily interest rate × number of days.
Interest rates may change once a calendar year and are the same for refunds and tax due:
| For periods
|January 1, 2015
|January 1, 2014
|January 1, 2013
|January 1, 2012
|January 1, 2011
|January 1, 2010
Note: interest accrues on any unpaid tax during an extension of time to file.
Interest will increase by one-third of 1 percent per month (4 percent yearly) on delinquencies if:
You file a return showing tax due, or the Department of Revenue has assessed an existing deficiency; and
- The assessment is not paid within 60 days after the notice of assessment is issued; and
- You have not filed a timely appeal.