Advance tax interest calculator (234B and 234C)
Enter your tax for the year, TDS and what you have paid so far. You see the instalment interest (section 234C, now 425), instalment by instalment, and the shortfall interest (section 234B, now 424).
Method per the Income Tax Department's FAQs on sections 423 to 426 · Reviewed by Regikart's CA team · 25 October 2026
After rebate, including surcharge and cess. Our income tax calculator gives this.
Interest: ₹2,100
section 425 (instalments) ₹2,100 · section 424 (shortfall) ₹0 · tax after TDS ₹2,00,000
section 425: instalment by instalment
| Due | Required | Paid | Interest |
|---|---|---|---|
| 15 June | ₹30,000 | ₹0 | ₹900 (3% of ₹30,000) |
| 15 September | ₹90,000 | ₹50,000 | ₹1,200 (3% of ₹40,000) |
| 15 December | ₹1,50,000 | ₹1,50,000 | Nil |
| 15 March | ₹2,00,000 | ₹2,00,000 | Nil |
section 424: you paid at least 90% of the tax as advance tax, so no interest for default applies. Interest is 1% a month or part of a month; the department rounds the amounts, so its figure can differ slightly. Shortfalls caused by capital gains, lottery winnings, dividends or new business income can be relieved if you pay the tax in the following instalments.
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Or send this on WhatsAppThe instalment schedule
| Due date | Cumulative amount | Interest if short |
|---|---|---|
| 15 June | 15% (no interest if at least 12%) | 3% of the shortfall |
| 15 September | 45% (no interest if at least 36%) | 3% of the shortfall |
| 15 December | 75% | 3% of the shortfall |
| 15 March | 100% | 1% of the shortfall |
Next date for Tax Year 2026-27: 15 December 2026, for 75% of the year's tax. Our advance tax service page explains who pays, the senior-citizen exemption and how to pay through e-Pay Tax.
Not sure of the year's tax? Work it out first with the income tax calculator, then subtract TDS from your Form 168 (the old Form 26AS).
Questions
Who has to pay advance tax?
Anyone whose tax for the year is ₹10,000 or more after TDS and TCS (section 404 of the 2025 Act). A resident senior citizen, aged 60 or more, with no business or professional income is not required to pay it.
What are the instalment dates?
15% by 15 June, 45% by 15 September, 75% by 15 December and 100% by 15 March. Presumptive taxpayers (the successor to sections 44AD and 44ADA) can pay the whole amount by 15 March.
How is interest under section 234C / 425 worked out?
1% a month on the shortfall: 3 months for each of the June, September and December instalments and 1 month for March. There is no June or September interest if you paid at least 12% and 36% respectively.
How is interest under section 234B / 424 worked out?
If advance tax paid by 31 March is less than 90% of the tax after TDS, interest of 1% a month or part of a month runs on the unpaid tax from 1 April after the year until you pay it or the income is assessed.
Which sections apply to my year?
FY 2025-26 (AY 2026-27) stays under the Income-tax Act, 1961: sections 234B and 234C. Tax Year 2026-27 onwards falls under the Income-tax Act, 2025: sections 424 and 425. The rates and method are the same.
I missed the June and September instalments. What now?
The interest on those two is already fixed, at 3% of each shortfall. Paying up to 75% by 15 December stops a further 3%, and paying 100% by 15 March avoids section 424 interest altogether.