Interest calculator under sections 234A, 234B and 234C
Find out how much interest you owe for filing late, for paying too little advance tax, and for paying instalments late. Enter your assessed tax and what you paid by each due date.
Calculate your interest
Assessment year 2026-27 (financial year 2025-26). Amounts are rounded down to the nearest ₹100 as the rules require. This is an estimate to plan with. Your return or the department's computation is final.
How each section works
| Section | When it applies | Rate and period |
|---|---|---|
| 234A | Return filed after the due date | 1% a month or part, from the day after the due date until filing, on tax still unpaid |
| 234B | Advance tax paid is less than 90% of assessed tax | 1% a month or part, from 1 April of the assessment year until filing, on the shortfall |
| 234C | An advance tax instalment was short or late | 1% a month: 3 months for the June, September and December instalments, 1 month for March |
Advance tax due dates
If you declare presumptive income under section 44AD or 44ADA, the whole advance tax is due in one instalment by 15 March.
Advance tax is not required when tax for the year, after TDS, is below ₹10,000, and resident senior citizens with no business income are exempt.
| Due by | Cumulative share of tax | 234C safe harbour |
|---|---|---|
| 15 June | 15% | No interest if at least 12% paid |
| 15 September | 45% | No interest if at least 36% paid |
| 15 December | 75% | — |
| 15 March | 100% | — |
Questions people ask
Is interest under 234A, 234B and 234C charged together?
Yes. They are separate. You can owe all three for the same year: 234C for late instalments, 234B for paying less than 90% in advance, and 234A for filing late.
Why is my amount rounded?
The rules round the amount on which interest is charged down to the nearest ₹100, and part of a month counts as a full month.
Does TDS count as advance tax?
TDS and TCS reduce the tax you have to pay in advance. Enter your tax after TDS, TCS and reliefs.