The rates of interest on overdue tax is a matter of some complexity. The Italian Parliament has, over the years, proposed simplification but the relevant draft legislation has not so far been enacted. Numerous different rates apply to different kinds of tax in different circumstances. The table below shows the base table of legal interest rates over the years, but individual taxes will likely have different rates applicable. Given the complexity you should always seek professional advice if you need an exact calculation.
| Table of Legal Interest Rates | |||
| From | To | Rate | Legislation |
| 21/04/1942 | 15/12/1990 | 5,00% | Art. 1284 cod.civ. |
| 16/12/1990 | 31/12/1996 | 10,00% | L. 353/90 e L.408/90 |
| 01/01/1997 | 31/12/1998 | 5,00% | L. 662/96 |
| 01/01/1999 | 31/12/2000 | 2,50% | Dm Tesoro 10/12/1998 |
| 01/01/2001 | 31/12/2001 | 3,50% | Dm Tesoro 11/12/2000 |
| 01/01/2002 | 31/12/2003 | 3,00% | Dm Economia 11/12/2001 |
| 01/01/2004 | 31/12/2007 | 2,50% | Dm Economia 01/12/2003 |
| 01/01/2008 | 31/12/2009 | 3,00% | Dm Economia 12/12/2007 |
| 01/01/2010 | 31/12/2010 | 1,00% | Dm Economia 04/12/2009 |
| 01/01/2011 | 31/12/2011 | 1,50% | Dm Economia 07/12/2010 |
| 01/01/2012 | 31/12/2013 | 2,50% | Dm Economia 12/12/2011 |
| 01/01/2014 | 31/12/2014 | 1,00% | Dm Economia 12/12/2013 |
| 01/01/2015 | 31/12/2015 | 0,50% | Dm Economia 11/12/2014 |
| 01/01/2016 | 31/12/2016 | 0,20% | Dm Economia 11/12/2015 |
| 01/01/2017 | 31/12/2017 | 0,10% | Dm Economia 7/12/2016 |
| 01/01/2018 | 31/12/2018 | 0,30% | Dm Economia 13/12/2017 |
| 01/01/2019 | 31/12/2019 | 0,80% | Dm Economia 12/12/2018 |
| 01/01/2020 | 31/12/2020 | 0,05% | Dm Economia 12/12/2019 |
| 01/01/2021 | 31/12/2021 | 0,01% | Dm Economia 11/12/2020 |
| 01/01/2022 | 31/12/2022 | 1,25% | Dm Economia 13/12/2021 |
| 01/01/2023 | — | 5,00% | Dm Economia 13/12/2022 |