Advance tax: how to avoid interest under 234B and 234C

If your total tax liability for the year, after TDS, is ₹10,000 or more, the law expects you to pay it in instalments through the year — not in one cheque at filing time. Salaried employees mostly escape this because TDS covers them; business owners, professionals, and anyone with meaningful capital gains, interest or rent do not.

The instalment calendar

What 234C charges — the instalment penalty

Fall short of an instalment and Section 234C (now Section 425 of the Income-tax Act, 2025, for tax year 2026-27 onwards) charges simple interest at 1% per month for three months on the shortfall (one month for the March instalment). There is sensible tolerance built in: no interest on the June instalment if you have paid at least 12% of the total, and none on September if you have paid 36%. Shortfalls caused by income you genuinely could not have foreseen — capital gains, lottery winnings, a new business's first profits — are excused if you pay tax on them in the instalment after the income arises.

What 234B charges — the bigger one

Section 234B (now Section 424 of the Income-tax Act, 2025) applies when your total advance tax plus TDS for the year comes to less than 90% of your assessed tax. It charges 1% per month from 1 April until you actually pay — which means a liability discovered at filing time in July already carries four months of interest, and one discovered in an assessment years later carries interest for the whole period. This is the expensive one, and the reason a March true-up matters.

A practical estimation method

Perfection is not required — coverage is. Each quarter, take your year-to-date profit, annualise it, apply your slab or corporate rate, subtract TDS already deducted, and pay the cumulative percentage due. In December and March, tighten the estimate with actuals: March is your last chance to reach 90% and switch off 234B entirely. For clients we maintain a simple quarterly tax-projection sheet alongside the books — ten minutes with a current month-end close makes the estimate almost mechanical.

Common traps

Three mistakes recur: forgetting that capital gains need tax in the next instalment after the sale; assuming TDS on professional fees covers the full liability (it rarely does — 10% deducted versus a 30% slab); and companies missing that even a loss year can owe advance tax under MAT/book-profit provisions. When in doubt, pay a conservative instalment — excess advance tax comes back with interest under Section 244A, while shortfalls compound against you.

A note on the new Income-tax Act, 2025

From tax year 2026-27, the Income-tax Act, 2025 replaces the 1961 Act. The advance-tax machinery is unchanged in substance, but the interest sections are renumbered — 234A becomes Section 423, 234B becomes Section 424 and 234C becomes Section 425. Income earned up to 31 March 2026 remains governed by the old Act, so both sets of numbers will be in use for a while; we cite both to keep things unambiguous.

Frequently asked questions

Who has to pay advance tax?

Anyone — individual, firm or company — whose tax liability for the year after TDS is ₹10,000 or more. Resident senior citizens with no business income are exempt.

What is the difference between 234B and 234C interest?

234C penalises missing the quarterly instalment pattern within the year (1% per month, briefly). 234B penalises finishing the year below 90% of your assessed tax and runs at 1% per month from 1 April until payment — usually the larger amount.

I sold shares in January. When is advance tax due on the gain?

In the remaining instalments after the sale — for a January gain, the 15 March instalment. Pay the full tax on the gain by then and no 234C interest arises on it.

Do presumptive taxpayers pay quarterly?

No. Businesses under 44AD and professionals under 44ADA pay their entire advance tax in one instalment by 15 March, one of the scheme's main conveniences.