Correct 730 after filing: how to fix it after the deadline

An error found today is not an error lost

Elena cleans houses in Borgo Mazzo. In early October, emptying her bag after a day's work, she found again an envelope with the receipts for the medicines paid for her father in 2025: an expense that was not in the 730 she filed in July. For a moment she thought she had thrown that money away. Then she came to the office, and the question we asked her is the same one we ask everyone: does the new account give you something or ask you for more?

When the mistake comes up after the 30 September deadline, you do not lose the right to put the return right. The law provides three tools — the 730 integrativo, the corrective Redditi form and the integrative Redditi form — and each has its own window of time. They are ordinary tools: we use them every week at the counter, with no automatic fines and no difficult words.

The question that decides everything: in your favour or against you?

Before talking about forms and boxes, at the counter we do two quick sums. The answers show the road to take by themselves, without studying anything.

If the corrected account gives you something

When the correction produces more credit, less debt or the same tax — as with Elena's receipts — the right form is the 730 integrativo, to be filed by 26 October 2026. Careful: this tool only goes in this direction. It is never used to tell the tax office that you owe more.

If the corrected account asks you for more

If instead an income was missing and the tax now goes up, the 730 is no longer enough: you move to the Redditi form. By 2 November 2026 it is filed as a corrective return, after that date as an integrative return. The result does not change: the return becomes the right one.

If only whoever pays your salary or pension is wrong

It often happens to those who change jobs in the summer: the 730 shows the old employer and the settlement does not arrive. In this case the 730 integrativo is used only to correct the withholding agent's details, and the window stays open until 26 October. Those who filed the pre-filled version online can fix this single point until 10 November 2026 as well, from the Agenzia delle Entrate website.

The real 2026 dates, in order

In 2026 there are only a few deadlines to remember. We put them in order, so you can see straight away where you are in the calendar today:

• Monday 26 October 2026: last day for the 730 integrativo. The normal deadline is 25 October, but this year it falls on a Sunday and shifts to the first working day. The form is filed only through a patronato CAF or an authorised professional, even if you sent the first return yourself.
• Monday 2 November 2026: deadline for the corrective Redditi form, which replaces the wrong 730 even when the debt goes up. 31 October is a Saturday and 1 November is a holiday, so the deadline shifts by two days.
• After 2 November 2026 the integrative Redditi form remains: for this year's returns the door is open until 31 December 2031, that is 31 December of the fifth following year.
• If instead you filed no return at all, within 90 days of 2 November the late return still stands: in practice until 31 January 2027, which falls on a Sunday and shifts to Monday 1 February 2027.
• Beyond 90 days the return is considered omitted, and the road becomes longer and more expensive: we look at that in the last part of the guide.

What changes for salary, pension and refund

Between the 730 and the Redditi form it is not just the name that changes: the way the money arrives changes too. It is a practical difference worth knowing before you choose.

• With the 730 integrativo the settlement passes through the withholding agent: the refund arrives in the payslip or the pension, and if there is a small debt it is withheld in instalments over the same months.
• With the Redditi form the account is closed separately: the credit is refunded by the Agenzia delle Entrate or used in offsetting, and any debt is paid with form F24, in one go or in instalments.
• The times change: the settlement in the payslip is quicker, the Redditi refund arrives after filing. If you are in a hurry to close the year, this is something to weigh up.

Franco, a pensioner from the Sant'Eusebio area, brought us his wife's case in October: a refund of 180 euro for forgotten medical expenses. With the 730 integrativo that money came back with the December pension, without filling in an F24 and without waiting for new forms. It is not always that quick, but it is the reason why it pays to act at once.

If the correction increases the debt: interest and penalties

Not every discovery is welcome. Sometimes the 730 had forgotten an income and the new account shows an amount to pay. This can be sorted too: you just need to know how the penalty account works.

• By 2 November 2026, with the corrective Redditi form: you pay the difference in tax plus legal interest, calculated day by day. The penalty for the delay is reduced by the ravvedimento operoso (voluntary correction), which lowers the penalty according to how quickly you act.
• After 2 November, with the integrative Redditi form: the logic is the same, but the interest account keeps running every day.
• If instead you filed no return at all: within 90 days of the deadline the late return still stands, with a fixed penalty of 250 euro. The ravvedimento operoso brings it down to 25 euro, when there is no tax to pay.
• After 90 days the return becomes omitted: the penalty is 120% of the tax due, with a minimum of 250 euro. If there is nothing to pay, it ranges from 250 to 1,000 euro.

Is the mistake in a 730 from years ago?

It happens more often than it seems. The bank, before granting a mortgage, asks for the last few years' returns. The Comune, for a nursery fee or a bonus, checks the ISEE. And out comes an old return with a wrong figure. For 730s from past years the integrativo no longer exists: there is only one door, and it is the integrative Redditi form of the year in which that 730 was filed.

The window is long but not endless: you can go up to 31 December of the fifth year after filing. A 730 filed in 2023, for example, can be integrated until 31 December 2028. Within that date you can recover forgotten expenses and correct wrong details, paying the difference if needed.

• The last return filed for that year, or its summary
• The documents from the wrong year: receipts, contracts, certificates, invoices
• Any notices or letters received from the Agenzia delle Entrate
• ID document, tax code and IBAN, to close everything in one go

If you cannot even remember what your return from three years ago contained, do not stop: book an appointment and we will line up the years to fix, one after another.

The questions that come up most often at the counter

Five short answers to the questions about a filed 730 that we hear most often. If your case is different — two jobs in the same year, NASpI, an inheritance — it is worth talking it over in person: we receive at Via Oreste Terenghi 21/23, 20092 Cinisello Balsamo (MI), Monday to Friday from 9:30 to 12:30 and from 15:00 to 19:00, always by appointment.

The document list for a correction

• A copy of the original return and the transmission receipt.
• Identity documents and tax code.
• The documents that were missing or wrong: receipts, certificates, income statements.
• An updated IBAN, if the account you gave has changed.
• The two questions to arrive having already decided: is the correction in your favour or against you?

That last point decides the route: if the corrected figures leave you in credit, the 730 integrativo is used; if they leave you in debt, or the difference is significant, you move to the Modello Redditi PF with its November dates. Bringing the answer to that question to the appointment shortens it and avoids a second round.

The online 730 integrativo: where it goes and which credentials

The integrative 730 is submitted through an authorised intermediary, like the ordinary return: you start from the return already transmitted, apply the corrections and send the new version. Credentials are used only to retrieve the data, not to replace the assistance — transmission is always done by the intermediary, with their signature.

If the correction increases what you owe, it is still worth doing when the amount is meaningful: an unclaimed credit is simply lost, while an undeclared debt only becomes more expensive with interest. The decision is not a matter of feel: it takes ten minutes of arithmetic with the documents in front of you.