ITR 2025: Due Date vs Last Date — What Missing Each Will Cost You

Two dates, two very different outcomes

One date costs you money. The other closes the door. That’s the real difference between the income tax return (ITR) filing due date and the last date for FY 2024-25 (AY 2025-26). If you care about ITR 2025 deadlines, here’s the only distinction that matters: miss September 15, 2025, and you pay; miss December 31, 2025, and you lose the option to file a regular or belated return for the year.

The Central Board of Direct Taxes (CBDT) moved the non-audit due date from July 31 to September 15, 2025, citing changes in return forms and the need to stabilize systems. This applies to most individuals, Hindu Undivided Families (HUFs), and other non-audit cases. The last date to file a belated or revised return remains December 31, 2025.

Where do things stand now? As of September 10, 2025, about 5.30 crore returns were filed, 4.99 crore verified, and 3.58 crore processed. Daily filings have slipped below 20 lakh in recent days, while tax professionals estimate more than 54 lakh returns per day are needed to comfortably meet the due date. Add in portal slowdowns, AIS/Form 26AS mismatches, and heavy traffic, and you get the stress taxpayers are talking about.

Are extensions likely? Requests have gone in from taxpayers and professionals, but there’s no sign of another push. The stance looks firm: September 15 stays.

Here’s what each date actually means for your money, your losses, and your options if you miss the cut.

Due date vs last date: what they actually mean, plus penalties, interest and your options

The due date (September 15, 2025): File by this date to avoid penalties and extra interest on unpaid tax. If your books don’t require audit, this deadline is yours. Audit and transfer pricing cases follow separate timelines, which typically fall later in the year; those taxpayers should stick to their specific statutory dates.

The last date (December 31, 2025): This is the final day to file a belated return under Section 139(4) or a revised return under Section 139(5) for AY 2025-26. After this date, the regular and belated windows shut.

What if you miss December 31? Your only formal route is the Updated Return under Section 139(8A). It comes with strings attached: you cannot use it to report a loss, reduce your tax liability, or claim a refund. You also pay additional tax—generally 25% of the aggregate of tax and interest if filed within 12 months after the end of the assessment year, or 50% if filed within 24 months—on top of the tax and interest already due. It’s a safety net, not a strategy.

Penalties and interest if you miss the due date but file by December 31:

• Late fee (Section 234F): Rs 5,000 for most taxpayers; Rs 1,000 if your total income is up to Rs 5 lakh.
• Interest (Section 234A): 1% per month or part of a month on unpaid tax, from September 16, 2025, until the date you file and pay. This is separate from the late fee.
• Advance tax/shortfall interest (Sections 234B/234C): If you didn’t pay enough advance tax, interest under these sections may also apply. Many salaried taxpayers escape 234B/234C because TDS covers most dues, but those with business income, capital gains, or large interest/dividend income should check their numbers.

Losses and carry-forward rules: Filing after the due date restricts what losses you can carry forward. For example, business and capital losses typically can’t be carried forward if the return is belated. If you have trading losses, capital losses from equity or property, or similar items, filing by September 15 matters more than you think.

Refund timing: Filing early does two things: it puts you ahead in the processing queue, and it avoids cutting into the interest you might otherwise get on your refund. Delays, especially with unpaid tax, raise your cost while slowing any money that’s due back to you.

Revised return vs belated return: If you file by the due date and later spot an error, you can revise the return up to December 31, 2025. If you miss the due date, you can still file a belated return until December 31, but your ability to carry forward certain losses is curtailed. Both revised and belated returns must be verified to be valid.

The compliance timeline at a glance for non-audit taxpayers:

• Original due date (extended): September 15, 2025 — file here to avoid late fee and extra interest on unpaid tax.
• Belated/revised window closes: December 31, 2025 — after this, the regular path is over.
• Updated Return (if needed): Up to 24 months after the end of the assessment year — but it costs extra and can’t be used to lower tax or claim refunds.

Why filings are stuck in the slow lane this year: Several taxpayers report AIS and Form 26AS mismatches (TDS credits not reflecting, duplicate entries, or missing interest/dividend data), portal timeouts during peak hours, and long waits for OTPs. For many, it’s taking multiple sessions to complete a return that normally takes an hour.

How to beat the rush and avoid errors:

• Pull your data first: Download AIS, TIS, and Form 26AS, and match them with bank statements, broker reports, and Form 16 before you even open the return form.
• Pick the right form: Salaried without complex income usually use ITR-1 or ITR-2; business/professional income typically means ITR-3; presumptive schemes use ITR-4. Choosing wrong slows processing and raises the odds of a notice.
• Reconcile TDS/TCS: If a TDS credit is missing in AIS/26AS, reach out to the deductor early. Don’t wait for the portal to auto-magically fix it.
• Compute tax and pay dues first: Clear any self-assessment tax before you submit. That cuts Section 234A interest to the bare minimum.
• Use the offline utility if the portal drags: Prepare your return offline, then upload during off-peak hours (early morning or late night).
• Pre-validate your bank account: Refunds only flow to pre-validated accounts. Fix this before filing so your refund isn’t stuck in limbo.
• E-verify immediately: Returns not verified within the allowed window are treated as not filed. Aadhaar OTP is the fastest route for most people.
• Keep proofs handy: Rent receipts, interest certificates, capital gains statements, donation receipts with 80G details, and health insurance premium proof. If a number looks high or low, you’ll want documents ready.
• Don’t ignore high-value items in AIS: If the system shows large deposits, trades, or property transactions, address them. Provide explanations where needed instead of hoping they’ll be overlooked.

Who should file even if there’s no big tax to pay? Apart from basic income thresholds, filing is expected if you’ve made high-value transactions, deposited large cash amounts, spent above certain limits on foreign travel or electricity, or own foreign assets. Many salaried people with adequate TDS also file to keep records clean and claim refunds.

For small businesses and professionals: Double-check whether presumptive taxation makes sense this year, but remember that switching in and out has conditions. Keep books, invoices, and payment proofs neat; mismatches with GST returns or bank flows are common triggers for scrutiny.

For investors: Reconcile broker P&L with AIS, and verify the cost of acquisition and corporate actions (splits, bonuses, rights) for accurate capital gains. If you plan to set off losses, the due date is your friend—miss it, and the carry-forward may vanish for certain categories.

For retirees and interest-income earners: Check if your bank deducted TDS at 10% and whether your final slab demands more tax. If you received SCSS interest, FD interest, or annuity payouts, match all figures with AIS and interest certificates.

What not to expect: Another blanket extension looks unlikely. If you leave filing for the final weekend, expect slower loads and longer OTP delays. The system can handle spikes, but not miracles.

The two dates are simple. September 15 is about avoiding needless costs and protecting your right to carry forward certain losses. December 31 is about keeping the door open at all. Miss the first, and you pay. Miss the second, and you run out of regular options.