IMU and TASI: how Italian property tax is worked out
IMU (Imposta Municipale Unica) is the main property tax paid by Italian property owners to their municipality, and TASI (Tassa sui Servizi Indivisibili) once covered municipal services like street lighting and maintenance. While TASI was absorbed into IMU in 2020, thousands of taxpayers still need to verify payments, handle late fees, and understand how their primary or secondary residence is taxed. This guide explains how to calculate both the base tax and the arrears plus interest owed to the comune.
TL;DR
- IMU is calculated annually by multiplying the cadastral income (rendita catastale) by the 5% revaluation and the category coefficient (160 for most residential categories), then applying the municipality rate expressed as a permille.
- Formula: IMU = Rendita × 1.05 × Coefficient × Rate‰ ÷ 1000 | Arrears = Base × (Legal interest + Sanction)
- Example 1: A secondary residence with cadastral income €800 — Revalued base: €800 × 1.05 × 160 = €134,400
How it works
IMU is calculated annually by multiplying the cadastral income (rendita catastale) by the 5% revaluation and the category coefficient (160 for most residential categories), then applying the municipality rate expressed as a permille. The tax is paid in two installments: the first by June 16, the second by December 16. TASI followed the same base and rate structure for indivisible services, with the taxpayer covering 90% and the tenant 10% when rented.
The math
Start from the cadastral income, apply the 5% revaluation and the category coefficient (160 for most residential categories), then multiply by the municipality permille rate. Divide by 1000 to obtain the annual tax. For arrears, apply statutory interest at the current annual legal rate prorated for the days of delay, plus the reduced penalty of the voluntary correction scheme (ravvedimento operoso).
The 5% revaluation applies to every cadastral income, and the category coefficient (160 for most residential categories) converts it into the taxable base before the rate is applied.
Examples
Example 1: A secondary residence with cadastral income €800
- Revalued base: €800 × 1.05 × 160 = €134,400
- Municipal rate: 10.6‰
- Annual IMU: €134,400 × 0.0106 = €1,424.64
- First installment: 50% = €712.32 due by June 16
Example 2: Late payment of a €500 IMU with 14 days delay
- Statutory interest at the 2026 legal rate (1.6% per year) for 14 days: €500 × 0.016 × 14/365 ≈ €0.31
- Ravvedimento sprint penalty: about 0.1% per day of delay → 1.4% = €7
- Total due: €500 + €0.31 + €7 = €507.31
- Penalty rates were revised on 1 September 2024; verify the current rates with your municipality
When to use it
✦ Property Owners and Buyers
Owners of second homes, rental properties, and commercial units estimate the annual IMU bill before buying or selling, and verify the amounts paid to the comune.
✦ Tax Advisors and Accountants
Professionals compute arrears and interest for clients who missed installments, producing figures for voluntary correction (ravvedimento operoso).
⚠ Common mistakes
- Using the Wrong Coefficient: Applying 160 to a primary residence can multiply the tax by more than 150 times the correct amount.
- Forgetting the Ownership Days: IMU is owed in proportion to the days of ownership in the year; full-year taxation is a common overpayment.
- Mixing TASI and IMU Bases: TASI used the same cadastral base but a different rate; treating them as identical can distort arrears calculations.
FAQ (2)
Is IMU due on my primary residence?
Since 2014 the first home is exempt from IMU in most cases, but luxury categories (A/1, A/8, A/9) still pay it.
What happened to TASI?
TASI was abolished in 2020 and its services were merged into IMU; late payments from previous years may still be disputed.
Sources & References
⚠ Financial Disclaimer
This tool provides estimates for informational purposes only and does not constitute financial, tax, or legal advice. Results may vary based on local regulations, rates, and individual circumstances. Always consult a qualified professional before making financial decisions.