IMU 2026: the second instalment due 16 December

What the December balance is and who must pay it

Mr Gennaro has been retired for three years and every autumn he makes the same gesture: he takes the June F24 receipt out of the drawer and lays it beside the calendar. Last November he discovered that the receipt is not enough: December brings the second instalment, and the figure is not a photocopy of June's. That is exactly what this guide deals with: what the second instalment settles, how to arrive at the right figure, and what to do when one instalment has fallen behind.

IMU is paid in two parts or in a single payment, as you prefer. If you pay in instalments, the first is the June advance and the second is the December balance: the balance is not a new tax, but the adjustment between the tax you owe for the whole of 2026, worked out with the rates the Comune has approved, and what you have already paid in June. If the rates do not change and the property is the same, the balance is almost equal to the advance; if something changed during the year, the December figure moves.

• anyone who owned a second home, a shop, an office, a warehouse, a building plot or land on 1 January 2026, in whole or in part;
• anyone who bought or sold during 2026: the balance is worked out only on the months the property was actually held;
• anyone whose main home is an A/1, an A/8 or an A/9: the exemption does not apply to these categories and the balance is due anyway;
• anyone who holds a property in joint ownership or bare ownership: each person pays their own share, and the usufructuary is treated as the holder for the purposes of the tax;
• heirs, for the year in which ownership passed to them: the balance for the year the estate is opened is split among the heirs themselves;
• non-commercial entities, for which the December instalment is the second advance of the year.

The 16 December 2026 deadline: what it covers

In 2026, 16 December falls on a Wednesday: it is a working day, so the deadline stays put and does not shift. For most people the December instalment is the balance, that is the remaining part of the year's tax; for non-commercial entities the same date is instead the second advance. In both cases the payment must be made by midnight on 16 December, and the F24 receipt is what counts at that date.

• 16 June 2026: advance, equal to the tax for the first half of the year worked out under the previous year's rules;
• 16 December 2026: balance, that is the difference between the tax for the whole year and the advance already paid;
• anyone who wants to close everything straight away can pay the whole of IMU 2026 in a single sum by June, without watching December;
• anyone who did not pay in June can put things right in December by paying the whole year with the ravvedimento operoso, as we explain further on;
• there is a minimum threshold: when the tax for the whole year does not exceed 12 euros the payment is not made, and the same goes for the balance;

Be careful not to confuse the balance deadline with those of other taxes falling in the same period: at the end of the year there are also the TARI, the car tax and the instalments of other payments, and at our desk we often see an F24 filled in with the wrong code for exactly this reason. One form for each tax, and within each form the right section: for IMU it is «IMU and other local taxes».

How the balance is worked out: cadastral income, rates, months and deductions

The balance takes four steps and needs no special tools: you just need the property's cadastral income, your ownership share, the months of the year you held it and the rate approved by the Comune where the property is located — not the one where you live. If you have already paid the June advance, the fifth element is the receipt for that payment: that is where the adjustment starts from.

Step 1: from cadastral income to the taxable base

The cadastral income is found in the land registry records or in the deed of purchase. For homes it is revalued by 5% and multiplied by 160; for other properties the multiplier changes, and for group D buildings the coefficient updated each year by decree of the Ministry of Economy is used. The result is the value the rate is applied to.

• cadastral income revalued by 5% and multiplied by the category coefficient: for a home it is 160;
• the rate of the Comune where the property is located is applied, at the level approved for 2026;
• it is multiplied by the ownership share: if the house belongs to two brothers at 50% each, each pays half;
• the months are counted: anyone who held the property for seven months pays seven twelfths, with a month that has begun counting in full if the holding lasted at least fifteen days;
• the deduction due, if any, is subtracted, and finally the June advance already paid is taken off: what is left is the balance.

Mr Gennaro's example

Gennaro has a flat let out in the Sant'Eusebio area with a cadastral income of 480 euros. Revalued by 5% and multiplied by 160, it comes to a taxable base of 80,640 euros. With the ordinary rate of 1.06% in our Comune, the tax for the year is about 855 euros. In June he paid half, some 427 euros; in December he pays the rest, a further 427 euros. If he had sold the flat in July, the balance would have been worked out only on the months of ownership, and the final figure would have been lighter.

If the June advance was not paid

It happens more often than you would think: June arrives, there are holidays, school expenses, and the IMU advance slips into the background. The good news is that the way to put it right is open and you do not need to wait for a notice from the Comune. It is called ravvedimento operoso: it means paying what is missing straight away, with a reduced penalty that grows the longer you wait, plus statutory interest calculated by the day. Alternatively, if the December balance is close, you can close everything in a single payment by paying the whole year's tax and regularising the missed advance in the same go.

• in the first fourteen days the penalty is 0.0833% for each day of delay, with a cap of 1.1662% on the fourteenth day;
• from the 15th to the 30th day: a penalty of 1.25% on the unpaid tax;
• from the 31st to the 90th day: a penalty of 1.39%;
• from the 91st day until the deadline for the 2026 IMU return, that is 30 June 2027: a penalty of 3.125%;
• beyond that deadline the penalty rises to 3.57%, and in every case statutory interest of 1.60% a year is added, calculated by the day from the day after the deadline to the day of payment;

These are the percentages set by Legislative Decree 87/2024, which reduced the ordinary penalty for omitted or late payments from 30% to 25%: if you do not put things right of your own accord and the Comune assesses the shortfall, the basic penalty is 25% plus interest. With the ravvedimento, on the other hand, tax, penalty and interest are paid together, with the same tax code as the property, ticking the «Ravvedimento» box on the form.

How to pay: F24, tax codes and code C707

For the balance you always use the F24 form, in the dedicated «IMU and other local taxes» section, and the payment can be made at a bank or post office counter, through home banking or with the Agenzia delle Entrate's F24 Web. No calculation arrives at your home: the reckoning is the taxpayer's, and if you do not want to do it alone we take care of it. Besides the tax code, which changes with the property category, the form must show the Comune code, the reference year and the box that tells the system you are paying the balance and not the advance.

The tax codes for the balance

• 3912: the luxury main home (categories A/1, A/8 and A/9) with its ancillary units;
• 3913: rural buildings for instrumental use, for which the rate in Cinisello Balsamo is 0.10%;
• 3914: farmland;
• 3916: building plots;
• 3918: other buildings, that is second homes, shops, offices and warehouses;
• 3925 and 3930: group D buildings for productive use, with the share reserved to the State up to 0.76% on code 3925 and the excess part, for Cinisello Balsamo 0.30%, on code 3930.

The three things not to get wrong

The cadastral code of the Comune of Cinisello Balsamo is C707: if another Comune's is written in, the payment ends up in the wrong place and you have to ask for a refund. The reference year is 2026, not the year in which you pay. And if the property is jointly owned, each person fills in their own line with their own share: a single payment made by only one of the owners leaves the others uncovered, and the Comune pursues them individually.

What to check before paying

Some mistakes on the balance come back every year at our desk, and they are exactly the ones that bring the Comune's friendly notice months later. The list below is short: five checks to make in ten minutes, before you press send on the form.

• do not treat the balance as a copy of the advance: it is an adjustment, and the figure changes if the rate approved during the year is not the same as the one used in June;
• do not forget to subtract the advance already paid: without that receipt you risk paying the same tax twice;
• do not use the old rates: for the 2026 balance in Cinisello Balsamo you use those approved by Town Council Resolution no. 28 of 26 February 2026;
• do not get the months wrong: anyone who bought, sold or received the property as a gift during the year pays only for the period of ownership, and the 200-euro deduction is prorated to the same months;
• do not leave the reliefs behind: a free loan to parents or children with a registered contract, agreed rent, historic or unusable properties lower the bill, but only if all the requirements are met.

Where to check your position

Two free tools are available to those who want to check for themselves: the Cinisello Balsamo Comune app that works out the tax and prepares the F24 payment form ready to print, and the LINKmate online counter, where with SPID or CIE you can consult your tax position and calculate, print and pay IMU. Watch out for update times: if you sold your house in November, check that the change has been recorded before trusting the statement you see on screen.

The questions we are asked most often about the balance

The five questions about the IMU balance that come up most often at the counter, with short answers. If your case is different — several properties, an estate to close, a flat taken on during the year — call us or message us on WhatsApp: the first consultation is free.