Advance Tax 2nd Installment Due 15 September 2026: Calculation Rules, Section 234B & 234C Interest Mitigation
Updated: Sep 6
As the mid-point of Financial Year 2026-27 approaches, corporate treasurers, business owners, and individual taxpayers must align their estimated tax cash flows with the statutory requirements of the Income-tax Act, 1961. Under Section 211, the deadline for remitting the second installment of Advance Tax is 15th September 2026.
Failing to estimate taxable business profits accurately or deferring payments past the 15th September deadline triggers automatic, non-waivable interest liabilities under Section 234C and Section 234B.
In this technical advisory, PGT & Associates (Chartered Accountants, Ahmedabad) outlines the calculation mechanics for the 45% cumulative threshold, the statutory "safe-harbor" buffers against Section 234C interest, exceptions for unanticipated capital gains, and a practical advance tax compliance framework.
1. Statutory Liability to Pay Advance Tax: Section 208
Under Section 208 of the Income-tax Act, advance tax is obligatory for any assessee whose estimated net tax liability for the financial year—after factoring in eligible Tax Deducted at Source (TDS), Tax Collected at Source (TCS), foreign tax relief (Section 90/91), and Minimum Alternate Tax (MAT) credits—equals or exceeds Rs. 10,000.
Senior Citizen Exemption (Section 207(2))
Resident senior citizens (individuals aged 60 years or above at any time during the financial year) who do not have any income chargeable under the head "Profits and gains of business or profession" (PGBP) are explicitly exempt from advance tax. Such individuals may discharge their entire tax obligation at the time of filing their return of income without incurring interest under Section 234B.
2. Installment Schedule & The 15th September Milestone
Under Section 211(1), corporate and non-corporate assessees (other than presumptive taxpayers under Section 44AD/44ADA) are required to remit advance tax across four quarterly installments:
Installment Due Date: On or before 15th June 2026 • Cumulative Percentage Required: Not less than 15% of advance tax • Applicable Relief / Safe Harbor Buffer: 12% buffer (No interest under 234C if $\ge 12\%$ paid)
Installment Due Date: On or before 15th September 2026 • Cumulative Percentage Required: Not less than 45% of advance tax • Applicable Relief / Safe Harbor Buffer: 36% buffer (No interest under 234C if $\ge 36\%$ paid)
Installment Due Date: On or before 15th December 2026 • Cumulative Percentage Required: Not less than 75% of advance tax • Applicable Relief / Safe Harbor Buffer: 75% strict threshold
Installment Due Date: On or before 15th March 2027 • Cumulative Percentage Required: 100% of advance tax payable • Applicable Relief / Safe Harbor Buffer: 100% of assessed tax
Presumptive Taxpayers (Section 44AD & 44ADA)
Eligible businesses and professionals opting for the presumptive taxation regime under Section 44AD(1) or Section 44ADA(1) are not required to pay advance tax quarterly. Under Section 211(1)(b), they may pay 100% of their advance tax in a single installment on or before 15th March 2027.
3. Interest Penalties for Shortfall or Deferment
Section 234C: Interest for Deferment of Installments
Section 234C levies simple interest at the rate of 1% per month (or part of a month) for a period of 3 months on the shortfall between the specified percentage and the amount actually paid:
Section 234C Interest Formula: Interest under 234C = (45% of Assessed Tax – Advance Tax Paid by 15 Sept) × 1% × 3 Months
#### The Statutory Safe-Harbor Buffer
To protect taxpayers against modest mid-year profit fluctuations, Section 234C provides a statutory cushion:
If the taxpayer pays at least 36% of the assessed tax on or before 15th September 2026, no interest under Section 234C is charged on the second installment, even though the formal target is 45%.
Section 234B: Interest for Default in Overall Payment
While Section 234C penalizes quarterly timing delays, Section 234B penalizes overall default at fiscal year-end:
If an assessee liable to pay advance tax fails to pay advance tax, or if the advance tax paid is less than 90% of the assessed tax, interest is chargeable at 1% per month from 1st April of the assessment year until the date of determination of total income or regular assessment.
4. Special Relief: Capital Gains & Unanticipated Incomes
Taxpayers often face substantial windfalls or capital gains mid-year that could not have been foreseen before the 15th June or 15th September deadlines.
Under the first proviso to Section 234C(1), no interest is levied for shortfall in advance tax if the shortfall is attributable to:
Capital gains (short-term or long-term under Section 45).
Winnings from lotteries, crossword puzzles, or online games.
Income under the head "Profits and gains of business or profession" where such income accrues or arises for the first time.
Dividend income (other than deemed dividend under Section 2(22)(e)).
Statutory Requirement: The taxpayer must pay the full tax liability on such unanticipated income in the remaining installments of advance tax that fall due after the date of receipt/accrual, or before 31st March if the income arises after 15th March.
5. Step-by-Step Advance Tax Calculation Methodology
Corporate finance teams should follow this systematic computation protocol:
Estimate Gross Total Income (GTI): Project revenue, operating profits, interest, capital gains, and other receipts for the full FY 2026-27 (1st April 2026 to 31st March 2027).
Apply Allowable Deductions: Deduct eligible business expenditures, depreciation under Section 32, and Chapter VI-A deductions.
Compute Gross Tax: Apply the applicable corporate tax rates (e.g., 22% under Section 115BAA plus 10% surcharge and 4% cess) or personal slab rates.
Deduct Withholding Taxes & Credits:
Total estimated TDS / TCS credits available in Form 26AS / AIS.
Foreign tax credits (FTC) under Section 90/90A/91.
MAT/AMT credits available for set-off under Section 115JAA / 115JD.
Determine Net Advance Tax Payable: If net tax $\ge$ Rs. 10,000, multiply by 45%.
Subtract 1st Installment Paid: Deduct tax remitted on or before 15th June 2026.
Generate Challan (Challan ITNS 280 / e-Pay Tax): Remit online via the Income Tax e-Filing Portal under Minor Head (100) Advance Tax.
6. Practical Compliance Checklist for 15th September 2026
[ ] Mid-Year Financial Closure: Reconcile books of accounts and revenues generated through 31st August 2026.
[ ] TDS/TCS Reconciliation: Verify 26AS and AIS to ensure all taxes deducted by customers/clients are documented.
[ ] Capital Gain Verification: Isolate share market, real estate, or mutual fund sales transacted between 1st April and 15th September 2026.
[ ] 36% Buffer Analysis: Ensure cumulative remittance equals at least 36% of the revised full-year projection to eliminate Section 234C exposure.
[ ] Electronic Payment Confirmation: Complete payment on the e-Filing portal before 11:59 PM on 15th September 2026 to guarantee date-stamping on Challan ITNS 280.
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About PGT & Associates
Established in 1996 and based in Ahmedabad, PGT & Associates is an independent Chartered Accountancy firm delivering specialized services in Corporate Direct Tax Planning, Advance Tax Modeling, Statutory Audit, Transfer Pricing, and International Taxation.
For institutional consultations, advance tax reviews, or corporate tax structuring, visit https://www.pgtandassociates.com or contact info@pgtandassociates.com.
Professional Disclaimer
This advisory is prepared strictly for informational awareness in compliance with the Chartered Accountants Act, 1949 and the Code of Ethics issued by the Institute of Chartered Accountants of India (ICAI). The contents do not constitute formal legal or tax counsel. Taxpayers should consult their professional tax advisors regarding their specific financial circumstances.
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