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Last Updated: 12/28/2016

Interest Rates

For calendar year 2017, the interest rate that is assessed or paid by the Department of Revenue is 4 percent.

If tax is paid late, interest is calculated from the regular due date and also applies to any penalties that are assessed on the unpaid tax. For individual income tax, the due date is April 15.

The department must pay interest on any refunds that are not issued within the period specified by state law, which is 90 days after the due date for income tax. If a return is filed late, interest is paid 90 days after the return is filed.

The chart below shows the interest rates for the last 11 years.
 
Year
Interest
Assessed on
Unpaid Taxes
Interest Paid
on Delayed
Refunds
​2017 ​4% ​4%
​2016 3%​​ ​3%
​2015 3%​ ​3%
​2014 3%​ 3%​
2013​ 3%​ 3%​
2012​ 3%​ 3%​
2011​ 3%​ 3%​
2010​ 3%​ 3%​
2009​ 5%​ 5%​
2008​ 8%​ 8%​
2007​ 8%​ 8%​
For more information, see Penalty Information for Individuals.