Interest Rates

On January 1 of each year, the Arizona Department of Revenue (ADOR) will add any outstanding interest as of that date to the principal amount of tax still owed. This compounding interest is then calculated on the new tax principal amount.

The department applies interest, compounded annually, in the same manner and at the same time as prescribed by the U.S. Internal Revenue Code (IRC), Section 6621. However, that rate of interest for both overpayments and underpayments for all taxpayers is the federal short-term rate, determined by the IRC, plus three percentage points.

PERIOD		COMPOUND POINT	DAYS/YEAR BASE	UNDERPAYMENT RATE		OVERPAYMENT RATE
BEGINNING	ENDING	COMPOUND POINT	DAYS/YEAR BASE	ANNUAL	DAILY	ANNUAL	DAILY
**INT THRU		SS
1/1/2018	3/31/2018		365	4%	0.0001096	4%	0.0001096
4/1/2018	6/30/2018		365	5%	0.0001370	5%	0.0001370
7/1/2018	9/30/18		365	5%	0.0001370	5%	0.0001370
			365
**INT THRU		SS
1/1/2017	3/31/2017		365	4%	0.0001096	4%	0.0001096
4/1/2017	6/30/2017		365	4%	0.0001096	4%	0.0001096
7/1/2017	9/30/2017		365	4%	0.0001096	4%	0.0001096
10/1/2017	12/31/2017		365	4%	0.0001096	4%	0.0001096
**INT THRU		SS
1/1/2016	3/31/2016		366	3%	0.0000820	3%	0.0000820
4/1/2016	6/30/2016		366	4%	0.0001093	4%	0.0001093
7/1/2016	9/30/2016		366	4%	0.0001093	4%	0.0001093
10/1/2016	12/31/2016		366	4%	0.0001093	4%	0.0001093
**INT THRU		SS
1/1/2015	3/31/2015		365	3%	0.0000822	3%	0.0000822
4/1/2015	6/30/2015		365	3%	0.0000822	3%	0.0000822
7/1/2015	9/30/2015		365	3%	0.0000822	3%	0.0000822
10/1/2015	12/31/2015		365	3%	0.0000822	3%	0.0000822
**INT THRU		SS
1/1/2014	3/31/2014		365	3%	0.0000822	3%	0.0000822
4/1/2014	6/30/2014		365	3%	0.0000822	3%	0.0000822
7/1/2014	9/30/2014		365	3%	0.0000822	3%	0.0000822
10/1/2014	12/31/2014		365	3%	0.0000822	3%	0.0000822
**INT THRU		SS
1/1/2013	3/31/2013		365	3%	0.0000822	3%	0.0000822
4/1/2013	6/30/2013		365	3%	0.0000822	3%	0.0000822
7/1/2013	9/30/2013		365	3%	0.0000822	3%	0.0000822
10/1/2013	12/31/2013		365	3%	0.0000822	3%	0.0000822
**INT THRU		SS
1/1/2012	3/31/2012		366	3%	0.0000820	3%	0.0000820
4/1/2012	6/30/2012		366	3%	0.0000820	3%	0.0000820
7/1/2012	9/30/2012		366	3%	0.0000820	3%	0.0000820
10/1/2012	12/31/2012		366	3%	0.0000820	3%	0.0000820
**INT THRU		SS
1/1/2011	3/31/2011		365	3%	0.0000822	3%	0.0000822
4/1/2011	9/30/2011		365	4%	0.0001096	4%	0.0001096
10/1/2011	12/31/2011		365	3%	0.0000822	3%	0.0000822
**INT THRU		SS
1/1/2010	12/31/2010		365	4%	0.0001096	4%	0.0001096
**INT THRU		SS
1/1/2009	3/31/2009		365	5%	0.0001370	5%	0.0001370
4/1/2009	12/31/2009		365	4%	0.0001096	4%	0.0001096
**INT THRU		SS
1/1/2008	3/31/2008		366	7%	0.0001913	7%	0.0001913
4/1/2008	6/30/2008		366	6%	0.0001639	6%	0.0001639
7/1/2008	9/30/2008		366	5%	0.0001366	5%	0.0001366
10/1/2008	12/31/2008		366	6%	0.0001639	6%	0.0001639
**INT THRU		SS
1/1/2007	12/31/2007		365	8%	0.0002192	8%	0.0002192
**INT THRU		SS
1/1/2006	6/30/2006		365	7%	0.0001918	7%	0.0001918
7/1/2006	12/31/2006		365	8%	0.0002192	8%	0.0002192
**INT THRU		SS
1/1/2005	3/31/2005		365	5%	0.0001370	5%	0.0001370
4/1/2005	9/30/2005		365	6%	0.0001644	6%	0.0001644
10/1/2005	12/31/2005		365	7%	0.0001918	7%	0.0001918
**INT THRU		SS
1/1/2004	3/31/2004		366	4%	0.0001093	4%	0.0001093
4/1/2004	6/30/2004		366	5%	0.0001366	5%	0.0001366
7/1/2004	9/30/2004		366	4%	0.0001093	4%	0.0001093
10/1/2004	12/31/2004		366	5%	0.0001366	5%	0.0001366
**INT THRU		SS
1/1/2003	9/30/2003		365	5%	0.0001370	5%	0.0001370
10/1/2003	12/31/2003		365	4%	0.0001096	4%	0.0001096
**INT THRU		SS
1/1/2002	12/31/2002		365	6%	0.0001644	6%	0.0001644
**INT THRU		SS
1/1/2001	3/31/2001		365	9%	0.0002466	9%	0.0002466
4/1/2001	6/30/2001		365	8%	0.0002192	8%	0.0002192
7/1/2001	12/31/2001		365	7%	0.0001918	7%	0.0001918
**INT THRU		SS
1/1/2000	3/31/2000		366	8%	0.0002186	8%	0.0002186
4/1/2000	12/31/2000		366	9%	0.0002459	9%	0.0002459
**INT THRU		SS
1/1/1999	3/31/1999		365	7%	0.0001918	6%	0.0001644
4/1/1999	9/30/1999		365	8%	0.0002192	7%	0.0001918
10/1/1999	12/31/1999		365	8%	0.0002192	8%	0.0002192
**INT THRU		SS
1/1/1998	3/31/1998		365	9%	0.0002466	8%	0.0002192
4/1/1998	12/31/1998		365	8%	0.0002192	7%	0.0001918
**INT THRU		SS
1/1/1997	12/31/1997		365	9%	0.0002466	8%	0.0002192
**INT THRU		SS
1/1/1996	3/31/1996		366	9%	0.0002459	8%	0.0002186
4/1/1996	6/30/1996		366	8%	0.0002186	7%	0.0001913
7/1/1996	12/31/1996		366	9%	0.0002459	8%	0.0002186
**INT THRU		SS
1/1/1995	3/31/1995		365	9%	0.0002466	8%	0.0002192
4/1/1995	6/30/1995		365	10%	0.0002740	9%	0.0002466
7/1/1995	12/31/1995		365	9%	0.0002466	8%	0.0002192
**INT THRU		SS
1/1/1994	6/30/1994		365	7%	0.0001918	6%	0.0001644
7/1/1994	9/30/1994		365	8%	0.0002192	7%	0.0001918
10/1/1994	12/31/1994		365	9%	0.0002466	8%	0.0002192
**INT THRU		SS
1/1/1993	12/31/1993		365	7%	0.0001918	6%	0.0001644
**INT THRU		SS
1/1/1992	3/31/1992		366	9%	0.0002459	8%	0.0002186
4/1/1992	9/30/1992		366	8%	0.0002186	7%	0.0001913
10/1/1992	12/31/1992		366	7%	0.0001913	6%	0.0001639
**INT THRU		SS
1/1/1991	3/31/1991		365	11%	0.0003014	10%	0.0002740
4/1/1991	12/31/1991		365	10%	0.0002740	9%	0.0002466
**INT THRU		SS
1/1/1990	12/31/1990		365	11%	0.0003014	10%	0.0002740
**INT THRU		SS
1/1/1989	3/31/1989		365	11%	0.0003014	10%	0.0002740
4/1/1989	9/30/1989		365	12%	0.0003288	11%	0.0003014
10/1/1989	12/31/1989		365	11%	0.0003014	10%	0.0002740
**INT THRU		SS
1/1/1988	3/31/1988		366	11%	0.0003014	10%	0.0002740
4/1/1988	6/30/1988		366	10%	0.0002740	9%	0.0002466
7/1/1988	9/30/1988		366	10%	0.0002732	9%	0.0002459
10/1/1988	12/31/1988		366	11%	0.0003005	10%	0.0002732
**INT THRU		SS
1/1/1987	3/31/1987		365	9%	0.0002500	8%	0.0002222
4/1/1987	9/30/1987		365	9%	0.0002466	8%	0.0002192
10/1/1987	12/31/1987		365	10%	0.0002740	9%	0.0002466
**INT THRU		SS
1/1/1986	6/30/1986		365	10%	0.0002778	10%	0.0002778
7/1/1986	12/31/1986		365	9%	0.0002500	9%	0.0002500
**INT THRU		SS
1/1/1985	6/30/1985		365	13%	0.0003611	13%	0.0003611
7/1/1985	12/31/1985		365	11%	0.0003056	11%	0.0003056