ITR Filing Checklist for FY 2025-26 (AY 2026-27): Documents, Deadlines and Common Mistakes

Filing an income tax return is mostly an exercise in matching. The department already knows most of what you earned, because banks, employers, mutual funds and brokers report it. Your job is to produce a return that agrees with those records and explains anything that does not. Almost every notice that lands in an inbox is the result of a mismatch, not of aggressive tax planning.

This checklist covers the return for FY 2025-26, which is assessment year 2026-27 — the income you earned between 1 April 2025 and 31 March 2026. It is still governed by the Income-tax Act, 1961. The new Income Tax Act 2025 applies only from April 2026 onward, so ignore its section numbers for this return.

1. The deadlines, as of 5 September 2026

These are the dates for AY 2026-27, current as of 5 September 2026. The 31 July date for ITR-1 and ITR-2 filers has passed and, as of today, the CBDT has not announced any extension, according to published deadline trackers and the absence of any circular on the Income Tax Department portal.

One genuinely new thing this year: the 31 August date for non-audit ITR-3 and ITR-4 filers is permanent, written into section 139(1) by the Finance Act, 2026. It is not a departmental extension granted by circular, so it will recur every year rather than being announced afresh. Freelancers and presumptive-scheme filers now have a structurally longer window than salaried filers.

2. Which ITR form applies to you

Picking the wrong form is the fastest way to have a return treated as defective. The rules for AY 2026-27:

3. The documents to collect first

Gather everything before you open the portal. Filing halfway and coming back tends to produce the errors in section 7.

• Form 16 from every employer you worked for during FY 2025-26. If you changed jobs, you need both — and you must combine the income, not file only the later one.
• Form 26AS, downloaded from the e-filing portal. This is the department's record of tax deducted against your PAN.
• AIS and TIS — the Annual Information Statement and Taxpayer Information Summary. These go far beyond 26AS, listing savings interest, dividends, mutual fund and share transactions, large card spends and property deals. Read the AIS before filing, not after a notice.
• Interest certificates from every bank and post office, covering savings account interest, fixed and recurring deposit interest. Savings interest is frequently forgotten because no TDS is deducted on it, yet it is fully reportable.
• Capital gains statements from your broker and from each mutual fund house or the RTA consolidated statement. You need the split between short-term and long-term, and the grandfathered cost where relevant.
• Home loan interest certificate from your lender, showing the principal and interest split for the year.
• Rent receipts and the landlord's PAN if you claim HRA above ₹1,00,000 of annual rent, under the old regime.
• Section 80C and 80D proofs — LIC premiums, PPF passbook, ELSS statements, tuition fee receipts, health insurance premium receipts — if you are filing under the old regime.
• Bank account details for the refund: account number, IFSC, and the account pre-validated on the portal.
• Aadhaar linked to PAN, with a working mobile number attached to the Aadhaar for OTP verification.

4. Filing, step by step

1. Log in at incometax.gov.in with your PAN as user ID.
2. Download AIS and Form 26AS from the "e-File" and "Services" menus and read them properly. Every income line in them must appear somewhere in your return or be explained.
3. Estimate your liability before you start entering data, so you can spot an implausible result. Our income tax calculator gives you a figure in a few seconds, and the old vs new regime tool shows which regime is cheaper for you.
4. Choose the regime. The new regime is the default. For a salaried filer, opting for the old regime is done inside the return. Business filers who want the old regime must file Form 10-IEA before the due date — miss that and the choice is gone for the year.
5. Select the correct form and year. Assessment year 2026-27, not 2025-26. This single dropdown causes more wasted evenings than any other field.
6. Use the pre-filled data as a draft, not as truth. Salary, TDS and often interest arrive pre-filled. Check each figure against your own documents and correct anything wrong.
7. Add what is missing. Savings interest, interest on a deposit that matured, dividend income, a small capital gain, rent from a second property — these are routinely absent from pre-filled data.
8. Claim deductions accurately. Only if you are on the old regime, and only with proof you could produce if asked.
9. Pay any balance tax through the e-Pay Tax facility before submitting, and enter the challan details in the return.
10. Preview, validate, submit — then move immediately to verification.

5. Verify within 30 days or it never happened

An unverified return is not a return. The time limit for e-verification, or for an ITR-V reaching the Centralised Processing Centre, is 30 days from the date of filing. Miss it and the return is treated as never filed, which means you have missed the deadline too.

Verification takes under a minute electronically. The usual routes are an OTP on the mobile number registered with your Aadhaar (individuals only), an electronic verification code generated through a pre-validated bank or demat account, or net banking. The physical alternative — signing the ITR-V and posting it to CPC, Bengaluru 560500 — is slower and riskier, because the 30 days run to the date CPC receives it, not the date you posted it.

6. Missed the date? Belated returns and section 234F

A belated return under section 139(4) can be filed until 31 December 2026. The costs:

On top of the fee, interest under section 234A runs at 1% per month, or part of a month, on unpaid tax from the due date until you file. "Part of a month" is literal: filing on the 2nd of a month costs the same as filing on the 30th, so if you are late, file at the start of a month rather than the end.

Filing late also costs you two things that money cannot restore. You cannot carry forward business or capital losses to set against future years — losses from house property are the exception and survive. And if you are a business filer who wanted the old regime, the Form 10-IEA window closes with the due date.

Past 31 December, the only route left is an updated return under ITR-U, available for up to 48 months from the end of the assessment year but carrying additional tax on top of what you owe. It exists to regularise omissions, not as a planning option.

7. Seven mistakes that generate notices

1. Omitting savings account interest. No TDS is deducted on it, so it never appears in Form 16 — but it sits in your AIS. Report it, then claim the section 80TTA deduction if you are on the old regime.
2. Filing on one Form 16 after a job change. Both employers gave you the basic exemption and deductions independently, so your combined liability is higher than either Form 16 suggests. This produces a demand almost every time.
3. Ignoring the AIS. Dividends, mutual fund redemptions and share sales are all reported to the department. A return that omits them is a mismatch waiting to be flagged.
4. Choosing ITR-1 with a short-term capital gain. Any amount of section 111A gain pushes you to ITR-2. The return may be accepted and later treated as defective.
5. Picking the wrong assessment year. AY 2026-27 for income earned in FY 2025-26. Filing under AY 2025-26 creates a return that matches nothing.
6. Claiming deductions you cannot evidence. Inflated HRA, rent paid to a relative with no actual payment trail, or 80C claims without documents. Scrutiny is increasingly automated and these are easy to test.
7. Forgetting to verify. Covered above, and still the single most avoidable failure in the whole process.

One more worth stating plainly: if your income is below the exemption limit but TDS was deducted — a common situation for students, retirees and anyone with a fixed deposit — file anyway. It is the only way to get that money back, and there is no penalty for filing when you were not required to.