Penalties & Interest

Interest Rates and Calculation

Interest is calculated using the number of calendar days from the original due date of the return until the tax is paid. Interest can be calculated using this formula:

(unpaid tax) x (interest rate) x (number of days) ÷ 365 = Amount of Interest Due

Note: By law, the International Fuel Tax Agreement (IFTA) has a different interest rate. See the instructions for completing Form TC-922, IFTA/Special Fuel User Tax Return, for the correct interest rate.

Interest Rates

Note: payments are applied first to penalties, secondly to interest and lastly to tax. See Rule R861-1A-18.

Calendar Year Interest Rate
2017 3% (.03)
2012-2016 2% (.02)
2010-2011 3% (.03)
2009 5% (.05)
2007-2008 7% (.07)
2006 6% (.06)
2005 4% (.04)
2004 3% (.03)
2003 5% (.05)
2002 6% (.06)
2001 8% (.08)
1999-2000 7% (.07)
1995-1998 8% (.08)
Oct 12, 1993 – Dec 31, 1994 6% (.06)
Before Oct 12, 1993 12% (.12)