ITR filing deadline today: Here's how much a one-day delay could cost you in interest and late fee

The countdown to the 31 July 2026 income tax return (ITR) filing deadline has entered its final phase, with the government yet to announce any extension, unlike last year. So far, more than 5.4 crore returns have been filed as taxpayers across the country rush to complete the process and verify their returns.

Although taxpayers who miss the deadline can still file a belated return by 31 December 2026, doing so incurs a penalty. Apart from a late filing fee, those with outstanding tax dues may also have to pay interest under the Income-tax Act. These charges apply even if the return is filed just one day after the due date.

Here's how much extra you may have to pay if you miss the 31 July deadline.

How the interest of late filing is calculated

If you fail to file your ITR by 31 July and have unpaid tax dues, interest under Section 234A may apply. The interest is charged at 1% per month or part of a month, calculated from the due date until the date you file your return and pay the outstanding tax.

According to Gaurav Makhijani, Managing Partner at MGA, the "part of a month" rule is particularly important because even a one-day delay can result in interest for an entire month.

In other words, whether you pay the outstanding tax on 1 August 2026 or any time during the following 30 days, interest for one full month may still apply on the unpaid amount.

Nishant Shanker, Tax Controversy and Dispute Resolution at Navraj Global Advisors, explained how the interest works under different scenarios:

— If the tax due is ₹10,000: Interest of ₹100 (1% of ₹10,000), plus any applicable late filing fee under Section 234F.

— If the tax due is ₹1 lakh: Interest of ₹1,000 (1% of ₹1,00,000), plus any applicable late filing fee.

— If the tax due is nil: No interest to be paid as there is no outstanding tax. However, a late filing fee under Section 234F may still apply.

“Interest is computed on the net tax payable after reducing any advance tax, TDS/TCS, eligible foreign tax relief, etc.,” Makhijani said, adding that those who have already paid their entire tax liability through TDS or advance tax will not be liable to pay interest under Section 234A, even if they file a belated return.

Late filing fee of up to ₹5,000

While a taxpayer is still allowed to file a delayed income tax return till the year-end, doing so will attract penalties between ₹1,000 and ₹5,000 under Section 234F of the Income-tax Act, depending on the income of the individual.

• For those with an income above ₹5 lakh, filing a belated return will incur a penalty of up to ₹5,000.
• For those with an income of up to ₹5 lakh, the maximum penalty for filing a belated ITR is ₹1,000.

If a person has an outstanding tax liability, this late filing fee applies in addition to the interest charged on the pending amount under Section 234A.