Calculate penalty interest under Section 234A (late ITR filing), 234B (insufficient advance tax), and 234C (deferred advance tax installments). Each section accrues 1% per month — shows breakdown and total interest owed.
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Section 234A/B/C Interest Calculator
Calculate penalty interest under Section 234A (late ITR filing), 234B (insufficient advance tax), and 234C (deferred advance tax installments). Each section accrues 1% per month — shows breakdown and total interest owed.
Tax & Payment Details
After surcharge + 4% cess
From Form 26AS / AIS
Advance Tax Paid (Cumulative by Quarter)
≥ 15% of total tax
≥ 45% of total tax
≥ 75% of total tax
≥ 100% of total tax
Self-assessment & Dates
Paid via challan 280 at filing
Jul 31 (non-audit) / Oct 31 (audit)
Actual filing / SAT-payment date
Always 1 April of the AY
Total Penalty Interest
Total penalty interest under sections 234A, B and C: ₹5,075.(234A: ₹0 · 234B: ₹1,750 · 234C: ₹3,325)
234A
₹0
Not applicable
234B
₹1,750
7 mo from Apr 1
234C
₹3,325
Per quarter
Total
₹5,075
Grand total
Per-quarter 234C Breakdown
| Quarter | Required | Paid | Shortfall | Months | Interest |
|---|---|---|---|---|---|
| Q1 (Jun 15) | ₹22,500 | ₹0 | ₹22,500 | 3 | ₹675 |
| Q2 (Sep 15) | ₹67,500 | ₹25,000 | ₹42,500 | 3 | ₹1,275 |
| Q3 (Dec 15) | ₹1,12,500 | ₹75,000 | ₹37,500 | 3 | ₹1,125 |
| Q4 (Mar 15) | ₹1,50,000 | ₹1,25,000 | ₹25,000 | 1 | ₹250 |
| 234C total | ₹3,325 | ||||
How to avoid 234A/B/C interest
- Pay advance tax on the Sec-211 schedule: 15% by Jun 15, 45% by Sep 15, 75% by Dec 15, 100% by Mar 15.
- File the ITR by the due date (Jul 31 / Oct 31) — even if you can't pay, file the return to stop 234A from accruing.
- Keep advance + TDS ≥ 90% of total tax before 31 March to side-step 234B entirely.
- If you receive a year-end bonus or capital gain, top up advance tax in the same quarter to avoid 234C.
Plan ahead
Calculate your advance tax schedule
Use the Advance Tax Calculator to figure quarterly instalments.
Penalty Interest by Section
Each section is independent; the rightmost bar is the sum you actually owe.
How It Works
This calculator estimates penalty interest under three sections of the Income-Tax Act, 1961 — all charged at 1% per month (or part of a month) on a simple-interest basis.
Section 234A — Late filing of the return
Triggered when the income-tax return is filed after the due date u/s 139(1) — typically 31 July for individuals not subject to audit and 31 October for audit cases. The base is the unpaid tax at the time of filing: total tax minus TDS minus advance tax minus self-assessment tax already deposited. If you have already discharged the full liability before the due date, 234A is zero even when the return itself is late.
Section 234B — Default in advance-tax payment
Triggered when the total advance tax paid is less than 90% of the assessed tax (total tax minus TDS). Interest accrues from 1 April of the assessment year until the date the shortfall is finally paid. The base is the full shortfall — not just the portion below 90%.
Section 234C — Deferment of instalments
Calculated separately for each of the four advance-tax instalment due dates: 15 Jun (15% required), 15 Sep (45%), 15 Dec (75%) and 15 Mar (100%). Any shortfall in a given quarter attracts 1% per month interest — 3 months for the first three quarters and 1 month for the final quarter. The quarterly figures are then totalled.
Frequently Asked Questions
Section 234A levies 1% per month (or part of a month) simple interest when an income-tax return is filed after the due date u/s 139(1). The interest is computed on the unpaid tax — total tax minus TDS, advance tax and self-assessment tax already deposited. If the entire tax is already paid by the due date, 234A is zero even if the return itself is late (this proviso was introduced by Finance Act 2017).
Part of Income Tax Calculators (FY 2026-27) — compare every related calculator in one place.