September 2026 Advance Tax: Due Date, Calculation & Common Filing Mistakes
TL;DR The September 2026 advance-tax instalment is due on 15 September 2026 for taxpayers liable to pay advance tax for Tax Year 2026–27. Under the normal instalment schedule, taxpayers should have paid at least 45% of their estimated annual advance-tax liability by 15 September, after considering the amount already paid in the earlier instalment. The Income Tax Department confirms that the advance-tax threshold under the new Income Tax Act, 2025 remains ₹10,000 or more of tax payable during the year. For Tax Year 2026–27, advance-tax payments are governed by the Income Tax Act, 2025. The new Act has not changed the underlying advance-tax policy; instead, it reorganises the provisions and introduces a formula for computing advance-tax liability under Section 405, while the liability threshold is provided under Section 404. Introduction September is an important tax-compliance month for taxpayers whose income is not completely covered through TDS. If you earn income from business, freelancing, professional services, rent, interest, capital gains, investments or other sources, your employer or payer may not deduct enough tax to cover your final liability. In such cases, the Income Tax Department requires eligible taxpayers to pay tax during the year itself instead of waiting until the income-tax return is filed. This is where advance tax becomes important. For Tax Year 2026–27, the September instalment has an additional significance because it is one of the first major advance-tax payments being made under the Income Tax Act, 2025, which came into force from 1 April 2026. The September deadline is straightforward: 15 September 2026 But the calculation is where many taxpayers make mistakes. A taxpayer does not simply pay 45% of gross income. Advance tax is calculated after estimating taxable income, applicable deductions, tax rates, surcharge and cess, while also giving credit for eligible TDS/TCS and advance tax already paid. Understanding the calculation correctly can help avoid unnecessary interest and a large tax payment later. What Is Advance Tax? Advance tax is income tax paid during the financial year in instalments based on estimated income for that year. Instead of calculating the entire tax liability after the year ends, taxpayers estimate their annual taxable income and pay tax progressively. This system is particularly relevant when income is received from sources such as: Business or profession Freelancing Consultancy Rental income Interest income Capital gains Dividends Investment income Commission Other income on which sufficient TDS has not been deducted For salaried individuals, advance tax is often substantially covered through TDS deducted by the employer. However, additional income can create an advance-tax liability. The Income Tax Department specifically highlights interest, rent, bonds and capital gains as examples of income that may increase the tax payable beyond salary TDS. September 2026 Advance Tax Due Date The second instalment of advance tax for Tax Year 2026–27 is due on 15 September 2026. The normal schedule is: Instalment Due Date Cumulative Advance Tax Required 1st 15 June 2026 15% 2nd 15 September 2026 45% 3rd 15 December 2026 75% 4th 15 March 2027 100% The September payment is therefore not necessarily 45% of your annual liability as a fresh payment. It is 45% cumulatively, after reducing the amount already paid in the June instalment. The Income Tax Department’s guidance confirms the 15%, 45%, 75% and 100% cumulative targets. Example Suppose your estimated total advance-tax liability for Tax Year 2026–27 is: ₹2,00,000 By 15 June, you should have paid: 15% = ₹30,000 By 15 September, cumulative payment should reach: 45% = ₹90,000 Therefore, the September instalment would be: ₹90,000 − ₹30,000 = ₹60,000 You do not pay another ₹90,000 in September. Who Needs to Pay Advance Tax? Under the Income Tax Act, 2025, advance tax becomes applicable where the tax payable for the year, calculated under the advance-tax provisions, is ₹10,000 or more. The threshold remains unchanged from the earlier framework. This can include taxpayers such as: Business owners If your business generates taxable profit and your final tax liability after applicable credits is ₹10,000 or more, advance tax may apply. Freelancers and consultants Professionals receiving payments with insufficient TDS can have a significant advance-tax liability. Investors Capital gains from: Shares Mutual funds Property Other investments can create additional tax liability during the year. Landlords Rental income can increase the overall tax liability beyond salary-related TDS. Salaried taxpayers with additional income A salaried person can also become liable if interest, capital gains, rental income or other taxable income creates a substantial tax shortfall after TDS. Who May Not Need Separate Advance Tax Payment? If your final tax payable for the year after considering applicable TDS/TCS and other eligible credits is below ₹10,000, the advance-tax obligation generally does not arise under the threshold. Senior citizens who do not have income from business or profession may also be exempt from advance-tax payment under the applicable provisions. However, taxpayers should calculate their actual liability rather than assuming that salary status or TDS automatically eliminates advance tax. How to Calculate September 2026 Advance Tax The most common mistake is to calculate advance tax directly on gross receipts. The correct approach starts with estimating your full-year taxable income. A practical calculation can be structured as follows: Step 1: Estimate total income for Tax Year 2026–27 Include all expected taxable income from: Salary Business Profession Rent Interest Dividends Capital gains Other taxable sources Step 2: Calculate taxable income Apply the relevant deductions, exemptions and allowable expenses according to the applicable tax regime and nature of income. Step 3: Calculate income tax Apply the applicable tax rates to taxable income. Step 4: Add applicable surcharge and cess Where applicable, include surcharge and health and education cess. Step 5: Reduce TDS/TCS credits Estimate the TDS and TCS that will actually be available as credit. Step 6: Reduce advance tax already paid Deduct the advance tax paid in June. Step 7: Determine September liability Ensure cumulative advance tax paid by 15 September reaches at least the applicable 45% target. Simple September Advance Tax Calculation Example Consider a consultant who estimates the following for Tax
