Missed the ITR Deadline? How to File a Belated Return Before 31 December

Missed the 31 July deadline for filing your income tax return? You can still file. A belated return under Section 139(4) can be filed any time up to 31 December 2026 for income earned in FY 2025-26 (assessment year 2026-27). It costs a late fee of ₹1,000 or ₹5,000 depending on your income, plus 1% per month interest on any unpaid tax — and, for salaried taxpayers, it locks you into the new tax regime. Here is exactly what a belated return costs, what you lose, and how to file one.

What a belated return is

A belated return is the same ITR form, filed on the same portal, after the due date has passed. Nothing about the form changes — you simply select “139(4) — Belated” instead of “139(1) — On or before due date” when asked which section you are filing under. The portal stays open for AY 2026-27 belated returns until 31 December 2026 (or until the tax department completes your assessment, whichever comes first — rare for salaried filers).

The late fee: ₹1,000 or ₹5,000

Section 234F charges a flat fee for filing late, and it applies even if your final tax payable is zero:

The fee is paid as part of self-assessment tax before you submit the return. If your total income is below the basic exemption limit, no fee is levied — unless you fall in a category that is required to file anyway (foreign assets, large deposits and the like), where a CA's advice is worth the consult.

Interest at 1% a month on unpaid tax

If any tax was still unpaid as of 31 July, Section 234A adds simple interest at 1% per month (or part of a month) from the day after the due date until you file. TDS already deducted by your employer doesn't count as unpaid — this bites only if you owed extra tax, for example on FD interest or capital gains your employer never saw.

Worked example: Riya earns ₹9 lakh and had ₹18,000 of tax still due on bank interest. She files her belated return on 20 October 2026 — August, September and October count as three months (a part month counts as a full one). Interest: ₹18,000 × 1% × 3 = ₹540. Late fee: income above ₹5 lakh, so ₹5,000. Total cost of missing the deadline: ₹5,540 — on top of the ₹18,000 tax itself. The fee dwarfs the interest for most salaried filers.

The hidden cost for salaried filers: no old regime

The new tax regime is the default. A salaried taxpayer can opt for the old regime — with its 80C, HRA and home-loan deductions — only in a return filed by the original due date. A belated return must use the new regime. If the old regime would have saved you money (run the regime comparison or the income tax calculator), that saving is gone for the year. For many people under ₹12.75 lakh this doesn't matter — the new regime already taxes them at zero — but for heavy-deduction filers it can cost far more than the ₹5,000 fee.

What else you lose

• Loss carry-forward: losses from capital gains or business cannot be carried forward to future years if the return is belated. The one exception is loss from house property, which survives.
• Refund interest: if a refund is due, the interest the department pays you on it is computed from your filing date, not from 1 April — a late filer earns less of it. The refund itself is unaffected; you still get it, and you still receive the usual intimation under 143(1) after processing.
• Revision window: a belated return can still be revised, but both share the same 31 December 2026 outer limit — file in late December and there is no room left to fix mistakes.

How to file it (10 minutes if your documents are ready)

• Log in at incometax.gov.in → e-File → Income Tax Return.
• Pick AY 2026-27, your ITR form (ITR-1 for most salaried), and section 139(4).
• Check the pre-filled salary, TDS and interest data against Form 16 and AIS; add anything missing.
• Pay self-assessment tax including the 234F fee and 234A interest the portal computes.
• Submit and e-verify within 30 days (Aadhaar OTP is fastest) — an unverified return is treated as never filed.

Missed 31 December too?

After 31 December 2026 the belated window shuts. The only route left is an updated return (ITR-U), which can be filed up to 48 months after the assessment year ends — but it comes with additional tax of 25% to 70% of the tax-plus-interest due, rising the longer you wait, and it cannot be used to claim a refund. It exists to let you come clean, not to save money. If you are in that territory, consult a CA.

Bottom line: a missed deadline is a fixable, priced mistake — ₹1,000 or ₹5,000 plus interest — not a catastrophe. The price rises sharply after 31 December, so if FY 2025-26 is still unfiled, file the belated return this week rather than in the last week of December.