| Due by | Cumulative | Pay by this date | This instalment | Paid by then | Interest (234C) |
|---|---|---|---|---|---|
| 15 Jun | 15% | ₹36.0K | ₹36.0K | ₹1.1K | |
| 15 Sep | 45% | ₹1.08 L | ₹72.0K | ₹3.2K | |
| 15 Dec | 75% | ₹1.80 L | ₹72.0K | ₹5.4K if unpaid | |
| 15 Mar | 100% | ₹2.40 L | ₹60.0K | ₹2.4K if unpaid |
234C is a fixed charge for paying an instalment late: 1% a month for three months on each of the first three shortfalls, one month on the last. It is final once the date passes; for dates still ahead the figure is a projection of what it will cost if nothing more is paid by then. 234B is different — it applies only if your advance tax came to less than 90% of the year's liability, and it runs at 1% a month from 1 April after the year ends until you actually pay. Mid-year it is a projection. We show the monthly rate rather than a total, because the total depends on a date only you know.
Advance tax is due when your annual tax liability exceeds ₹10,000. Pay 15% by 15 Jun, 45% (cumulative) by 15 Sep, 75% by 15 Dec and 100% by 15 Mar. Shortfalls attract interest under sections 234B/234C. Presumptive taxpayers (44AD/44ADA) can pay 100% by 15 Mar in one go.
From 1 April 2026 the deferment interest below sits in section 425 of the Income-tax Act, 2025. The familiar 234B/234C (and 44AD/44ADA) labels are kept because that is what notices and advisers still use; the 2025 Act renumbers them and speaks of the "tax year" rather than the assessment year.
Advance-tax rules · last verified September 2026. This is a calculator, not tax advice — check the figures with your CA before you pay.