Interest Under Section 234A, 234B, 234C: Guide 2026

Suppose your assessed tax for FY 2025-26 (AY 2026-27) works out to ₹1,00,000 after TDS, you paid zero advance tax during the year, and you file your return five months late. The Income Tax Department will not just want the ₹1,00,000. It will add interest under three separate sections, and by the time you pay, the bill can cross ₹14,000 in interest alone. This guide walks through that exact calculation, rupee by rupee, then explains what each section does. 💸

Take the same numbers throughout: assessed tax (net of TDS) = ₹1,00,000, no advance tax paid, return filed late.

Section 234C (deferment of advance tax instalments, charged within the financial year). You missed every quarterly instalment, so each shortfall attracts 1 percent per month:

1. 1st instalment due 15 Jun: 15% of ₹1,00,000 = ₹15,000 shortfall → 1% × 3 months = ₹450
2. 2nd instalment due 15 Sep: 45% = ₹45,000 shortfall → 1% × 3 months = ₹1,350
3. 3rd instalment due 15 Dec: 75% = ₹75,000 shortfall → 1% × 3 months = ₹2,250
4. 4th instalment due 15 Mar: 100% = ₹1,00,000 shortfall → 1% × 1 month = ₹1,000
5. 234C total = ₹5,050

Section 234B (short payment of advance tax, charged from 1 April of the assessment year). Because you paid less than 90% of assessed tax, the whole ₹1,00,000 attracts 1 percent per month from 1 April until you pay. Say you pay four months later:

• ₹1,00,000 × 1% × 4 months = ₹4,000

Section 234A (return filed after the due date, on the still-unpaid tax). Filed five months late with the tax still outstanding:

• ₹1,00,000 × 1% × 5 months = ₹5,000

Grand total interest = ₹5,050 + ₹4,000 + ₹5,000 = ₹14,050, on top of the ₹1,00,000 tax. These three sections stack, and 234B and 234C are not netted against each other. That is why a single missed year hurts. ⚠️

All three sit in the Income Tax Act, 1961, and all three charge simple interest at 1 percent for every month or part of a month. A single day into a new month counts as a full month.

Charged when you file your return after the due date and tax is still unpaid. Interest runs at 1% per month from the day after the due date until you actually file (or pay), on the outstanding tax. Key nuance: 234A is compensatory, so if your self-assessment tax was already paid by the due date and only the return is late, the 234A amount is nil. It bites only on tax that remains unpaid.

Charged when the advance tax you paid is less than 90% of your assessed tax. Interest runs at 1% per month from 1 April of the assessment year until the tax is paid, on the shortfall. Advance tax itself is only required when your net tax liability is ₹10,000 or more in the year, so small liabilities escape this entirely.

Charged when you pay your advance tax late within the year, missing the quarterly schedule. The cumulative targets are 15% by 15 June, 45% by 15 September, 75% by 15 December and 100% by 15 March. A shortfall at each date attracts 1% per month, charged for 3 months on the first three instalments and 1 month on the last.

There is a built-in cushion: for the first two instalments, no 234C interest applies if you have paid at least 12% by 15 June and at least 36% by 15 September (instead of the full 15% and 45%). This relief recognises that early-year income is hard to estimate.

1. ① Estimate your full-year income early and pay advance tax on the 15/45/75/100 schedule. Use our advance tax due dates and calculation guide.
2. ② If income is lumpy, at least clear the 12% and 36% safe-harbour by 15 June and 15 September to dodge 234C on the early instalments.
3. ③ Pay any remaining self-assessment tax before the return due date, which zeroes out 234A even if the return itself slips.
4. ④ Make sure you are filing the right form first; see which ITR form to file for AY 2026-27.
5. ⑤ Track the deadline with the deadline calculator so a late filing never triggers 234A.

Yes. Sections 234A, 234B and 234C are charging provisions in the Income Tax Act, 1961, and they apply to whatever tax results from your return. The regime you choose, old or new, decides the tax figure, and the interest sections then apply on top of that figure. So even if your liability is low because of the Section 87A rebate under the new regime, any interest under 234A/B/C is still computed on the tax that remains after the rebate. If you are weighing regimes, read our guide to switching regime using Form 10-IEA.

For a plain-language tour of your information and grievance rights as a taxpayer, keep The RTI Playbook handy.

Yes. They cover different defaults and stack. In the worked example above, a single year of zero advance tax and a late return triggered 234C (₹5,050), 234B (₹4,000) and 234A (₹5,000) together, totalling ₹14,050 in interest on a ₹1,00,000 liability.

Simple. All three sections charge 1 percent for every month or part of a month on a simple basis. A part of a month is always rounded up to a full month, so even one extra day adds a whole month of interest.

If the tax was fully paid by the due date and only the return is late, the 234A interest is nil because there is no unpaid tax for it to run on. You may still face a separate late-filing fee under Section 234F, but that is not 234A interest.

No. The regime only sets your tax amount. Once the tax is computed, 234A, 234B and 234C apply on top regardless of whether you chose the old or new regime.

Only when your net tax liability for the year is ₹10,000 or more. Below that, advance tax is not due, so 234B and 234C cannot be charged. Resident senior citizens with no business or professional income are also exempt from advance tax.

For the first two instalments, no 234C interest is charged if you have paid at least 12 percent of assessed tax by 15 June and at least 36 percent by 15 September, even though the standard targets are 15 percent and 45 percent. This cushion covers small estimation errors early in the year.

• Income Tax Department, Interest under Sections 234A/234B/234C/234D: https://www.incometaxindia.gov.in/interest-under-sections-234a/234b/234c/234d
• Income Tax Department tutorial, Interest payable by the taxpayer: https://incometaxindia.gov.in/tutorials/6-interest%20payable%20by%20the%20taxpayer.pdf
• Income Tax Department, Interest and Fees: https://www.incometaxindia.gov.in/w/interest-and-fees
• Income Tax Act, 1961, Sections 234A, 234B, 234C

• Advance tax due dates and calculation
• Which ITR form to file for AY 2026-27
• Switch tax regime using Form 10-IEA
• Deadline calculator
• Section 87A rebate in the new regime
• The RTI Playbook