IMU in Italy: a guide for foreign owners

written by Riccardo Virga 

IMU calculation: a step-by-step guide

One of the first questions our clients ask is how the IMU tax is calculated. The process is logical but requires specific data points unique to your property. We will walk you through the formula, explain each component, and provide a practical example.

The IMU is based on cadastral value, not market value

Crucially, the IMU calculation is not based on the commercial or market value of your real estate. Instead, it is based on the property’s official land registry value, known as the cadastral value. This value is derived from a figure called the Rendita Catastale.

The IMU formula explained

The formula for your annual Italian municipal property tax is as follows:

(Rendita Catastale x 1.05) x Multiplier = Taxable Base
Taxable Base x IMU Rate (%) = Annual IMU Payment

Let’s break down each component:

A practical example: calculating IMU for a holiday home

Let’s apply the formula to a real-world scenario to make the IMU calculation clear.

• Property: a two-bedroom apartment of around 90 square metres in the historic centre of Florence. You are a non-resident, so this is taxed as your seconda casa.
• Rendita Catastale: From the Visura Catastale, you see this is €1,200.
• Municipality: Comune di Firenze, which, like many major cities, applies the maximum IMU rate.
• IMU Rate: 1.06% (or 10.6 per mille).

Here is the step-by-step IMU calculation:

Step 1 (Revalue the Cadastral Income):
First, we revalue the official cadastral income figure by 5%.
€1,200 x 1.05 = €1,260

Step 2 (Apply the Multiplier to Find the Taxable Base):
Next, we apply the standard residential multiplier to find the full taxable value of the property.
€1,260 x 160 = €201,600 (This is your Taxable Base)

Step 3 (Apply the Local IMU Rate):
Finally, we apply the specific IMU rate set by the municipality of Florence.
€201,600 x 1.06% = €2,136.96

What foreign owners should do before 16 December 2026

• Confirm the property is correctly classified as a seconda casa and that no exemption genuinely applies.
• Check your comune’s final 2026 IMU resolution on the Ministry of Finance portal, since the December balance uses this rate, not last year’s.
• Verify your rendita catastale and that the tax code (3918 for most second homes) and comune code on your F24 are correct.
• Arrange your payment route from abroad now, rather than in the week of the deadline, as international transfers need the correct IBAN and reference format.
• Check whether an IMU declaration was ever required for your property, particularly if you bought, renovated or changed its use in 2025.

Expert tip: what “international convention” actually means

This is the most misunderstood reduction we deal with. The pension that qualifies is a totalised one, meaning it was calculated by combining contribution years paid in Italy with contribution years paid in another country under a social security agreement between the two. In practice, this describes someone who worked part of their career in Italy and part abroad, and whose pension was built from both sets of contributions.

Two common situations do not qualify. If your only pension is a foreign one, such as a UK state pension or a US private pension, with no Italian contributions behind it, the reduction does not apply. The same is true if your only pension is an ordinary Italian INPS pension. In both cases there has been no totalisation, and without totalisation there is no 50% reduction, however long you have lived abroad.

IMU tax: Frequently Asked Questions

1. The article mentions the IMU payment. Do I also need to file an IMU Declaration?

This is a critical point we often clarify for new owners, as the payment and the declaration are two separate obligations. An IMU Declaration (Dichiarazione IMU) is not an annual requirement, but it is mandatory when there is a change that affects the tax calculation which the municipality is not already aware of. You must file this declaration with your local municipality by June 30th of the year following the change.

In our practice, the most common triggers for foreign owners are:

• Initial purchase: When you first acquire the property.
• Significant renovations: If a renovation changes the property’s characteristics or Rendita Catastale.
• Change of use: For example, converting part of a home into a small office or rental unit.

Failing to file a required IMU Declaration can lead to penalties, even if you have been making the correct IMU payment.

Please note: from 1 January 2027 the penalty framework for failing to file an IMU declaration, or for filing an inaccurate one, is being recalibrated. If you have a declaration outstanding from an earlier change, resolving it before the end of 2026 is the prudent course.

2. I am buying/selling my property this year. Who is responsible for the IMU payment?

This is a very common question, and Italian law is quite clear. The IMU tax for the year of a real estate transaction is divided between the buyer and the seller based on the number of months of ownership. The month of the sale itself is counted in favour of the party who owned the property for more than 15 days of that month.

Here is a practical example:

• You sell your Italian property, with the final deed (Rogito) signed on April 20th.
• The seller (You): You owned the property for January, February, March, and April (as you owned it for more than 15 days in April). You are responsible for paying the IMU for 4 months of the year.
• The buyer: The new owner is responsible for the remaining 8 months, from May to December.

Our role during a property transaction includes ensuring this pro-rata calculation is made correctly and that both parties are clear on their respective obligations for both the June and December payment deadlines. If the sale completes in the second half of the year, the pro-rata split applies directly to the December saldo, which makes it worth settling the division in the deed rather than leaving it to be reconciled afterwards.

3. I inherited a property with my two siblings. How do we manage the IMU payment?

Co-ownership is a very common scenario, especially for inherited Italian property. It is essential to understand that under Italian law, the IMU liability is divided pro-quota, meaning each owner is individually and separately responsible for the tax corresponding to their share of ownership.

If you and your two siblings each own a one-third share, you are only legally responsible for paying one-third of the total annual IMU tax. You are not liable if one of your siblings fails to make their IMU payment. In our experience, the most effective way to manage this is for one party to coordinate the full IMU calculation and then provide the precise amount due and the F24 form details to the other co-owners, so each can arrange for their specific share to be paid.

4. I’ve just discovered I own a property and I’m worried IMU has never been paid. What should I do?

This is a serious situation, but it is absolutely fixable. Ignoring the problem is the worst possible course of action, as the municipality will eventually issue a tax assessment (avviso di accertamento) with heavy penalties (often 30% of the unpaid tax) plus interest.

The correct approach is a proactive one. We can assist by:

1. Conducting a full historical analysis to determine exactly what is owed for the past five years (the typical statute of limitations).
2. Utilising the “voluntary correction” mechanism (Ravvedimento Operoso) to pay any overdue tax with significantly reduced penalties.
3. Communicating with the relevant municipality and the Italian Revenue Agency (Agenzia delle Entrate) on your behalf to resolve the outstanding liability.

In our practice, we have successfully guided many clients through this process. Taking decisive action to correct past non-compliance is the most effective way to protect your property from further penalties or, in worst-case scenarios, a tax lien.