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Last Updated: 11/1/2017

Interest Rates

For calendar year 2018, 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 for the unpaid tax.
For more information, view Penalty Information for Businesses.

The department must pay interest to taxpayers on any refunds that are not issued within the period specified by state law.

The chart below shows interest rates for the last 10 years:  

​Year

​Interest Assessed

on Unpaid Taxes

​Interest Paid

on 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%