Income tax guides
23 guides written for people who want a straight answer. Every figure is dated and sourced, and where the published sources disagree with each other we say so rather than picking one quietly.
Written for FY 2026-27 under the Income-tax Act, 2025. Where a rule changed this year — and several did — the guide says what it was before, because a return you file now may still be governed by the old position.
Which ITR form
Seven forms, and the thing that matters is what disqualifies you from the one you expected to use.
ITR-1 (Sahaj) — who can use it, and what throws you off it ITR-1 Sahaj is for salaried people with one house property and income up to ₹50 lakh. Here is the full list of things that disqualify you from using it. ITR-2 — for capital gains, multiple properties and foreign assets ITR-2 is for individuals with capital gains, more than one house property, foreign income or assets, or income above ₹50 lakh. No business income. ITR-3 — business and professional income with full accounts ITR-3 is for individuals and HUFs with business or professional income who maintain books of account. Includes profit and loss and balance sheet schedules. ITR-4 (Sugam) — presumptive taxation for small business and professionals ITR-4 Sugam is for small businesses and professionals using presumptive taxation under sections 44AD, 44ADA or 44AE. No books, no audit, income up to ₹50 lakh. ITR-5 — partnership firms, LLPs and associations ITR-5 is filed by partnership firms, LLPs, associations of persons and bodies of individuals. Covers partner remuneration under section 40(b) and firm-level tax. ITR-6 — the company return ITR-6 is filed electronically with digital signature by every company except those claiming exemption under section 11. Requires audited accounts and a tax audit report. ITR-7 — trusts, institutions and political parties ITR-7 is filed by charitable and religious trusts, political parties, research institutions, universities and colleges claiming exemption under the Income-tax Act.
Deadlines and penalties
What each missed date costs — and the loss that is permanent rather than merely expensive.
Income tax return deadlines — every date that matters ITR due date for individuals is 31 July. Belated returns until 31 December, revised until 31 March. Here is every deadline and what each one costs to miss. Section 234F — the late filing fee, and what sits alongside it Section 234F charges ₹5,000 for filing after the due date, reduced to ₹1,000 where total income does not exceed ₹5 lakh. Interest under 234A applies separately. Belated return — what you can still do after 31 July A belated return under section 139(4) can be filed until 31 December of the assessment year, with a late fee and interest. Losses cannot be carried forward. ITR-U — the updated return, and what it costs An updated return under ITR-U can be filed up to 48 months from the end of the assessment year, with additional tax of 25% to 70% depending on the delay.
Notices from the department
What each section number actually means, and how urgently it needs answering.
Section 143(1) intimation — usually not what people fear A section 143(1) intimation is an automated comparison of your return against the department's records. Most confirm the return. Here is how to read one. Section 139(9) — your return is defective A section 139(9) notice means your return is defective and must be corrected within the time allowed, or it is treated as never having been filed at all. Section 245 — when your refund is set against an old demand A section 245 notice tells you the department intends to set your refund against an earlier outstanding demand. You have a limited window to disagree. Section 148 — reassessment of an earlier year A section 148 notice reopens an earlier year because the department believes income escaped assessment. This is the serious end of the notice spectrum.
Forms and statements
Form 16, Form 26AS, AIS and the rest — what to check before you file, not after.
Form 16 — what each part means and what to check Form 16 is your employer's TDS certificate. Part A shows tax deposited, Part B shows the salary breakdown. Here is how to check it before you file. Form 26AS — the tax credit statement that governs your refund Form 26AS is the department's record of tax deducted, collected and paid against your PAN. If a credit is not in 26AS, you cannot claim it in your return. AIS and TIS — what the department already knows about you The Annual Information Statement reports your financial transactions to the department. Mismatches between AIS and your return are the main cause of notices. Form 15G and 15H — when you may file them, and when you must not Form 15G and 15H are declarations that stop your bank deducting TDS on interest. Filing one when your income is actually taxable creates a bigger problem. Form 12BB — the declaration that sets your monthly TDS Form 12BB declares your deductions to your employer so TDS is calculated correctly. Missing it does not lose the deduction — the return still claims it.
Deductions
Limits, conditions, and the errors that quietly cost people the whole claim.
Section 80C (now Section 123) — the ₹1.5 lakh deduction Section 80C allows up to ₹1,50,000 of deductions for investments and specified payments. It is renumbered Section 123 under the Income-tax Act 2025. Section 80D — health insurance premiums and medical expenditure Section 80D allows ₹25,000 for self and family, rising to ₹1,00,000 where both you and your parents are senior citizens. Old regime only. Section 80CCD(1B) — the extra ₹50,000 for NPS Section 80CCD(1B) gives an additional ₹50,000 deduction for National Pension System contributions, over and above the ₹1.5 lakh section 80C limit.