Advance tax is the principle that income tax is paid through the year, not at year-end. Sections 234B and 234C of the Income-tax Act, 1961 are the interest provisions that compensate the government for shortfalls. Both are levied automatically when the ITR is processed — the e-filing portal computes them — and both surface most often for taxpayers with a mix of income types (salary + capital gains, business + investments, salaried with foreign income).
The advance tax framework
Section 208 of the Act requires every assessee whose advance-tax liability is Rs 10,000 or more in a financial year to pay tax through the year. Senior citizens (age 60+) who do not have business income are exempt from advance tax under Section 207(2) — they can pay their full liability through self-assessment tax with the ITR. The exemption does not extend to senior citizens with business income.
The four advance-tax instalments under Section 211 are:
- 15% by 15 June
- 45% (cumulative) by 15 September
- 75% (cumulative) by 15 December
- 100% (cumulative) by 15 March
Assessees opting for the presumptive scheme under Section 44AD or 44ADA pay 100% in a single instalment by 15 March.
Section 234B — for not paying enough advance tax
Section 234B applies when advance tax paid during the year is less than 90% of the assessed tax. The interest is 1% per month (simple) on the shortfall, from 1 April of the assessment year until the date the assessed tax is paid.
Example: a salaried taxpayer with a Rs 3 lakh ITR liability who had Rs 2.5 lakh TDS deducted by the employer, no advance tax paid, and pays the balance Rs 50,000 in July as self-assessment tax. The 90% threshold is Rs 2.7 lakh. TDS of Rs 2.5 lakh is below that — shortfall is Rs 50,000 (Rs 3 lakh assessed tax minus Rs 2.5 lakh TDS). 234B interest accrues at 1% per month from 1 April to the payment date in July — roughly four months × 1% = 4% × Rs 50,000 = Rs 2,000.
If the shortfall is small enough that TDS covered at least 90% of the assessed tax, 234B does not apply. This is the “90% rule.” The intent is to allow salaried taxpayers whose TDS substantially covers their liability to avoid the advance-tax mechanism entirely.
Section 234C — for paying advance tax late
Section 234C applies even when the total advance tax for the year is paid, but the instalments were paid late. The interest is 1% per month for three months on each of the first three shortfalls, and 1% for one month on the final shortfall — computed cumulatively at each due date.
The shortfall test at each instalment:
- By 15 June: less than 12% of total tax paid — interest on shortfall to 15% of tax (3-month interest)
- By 15 September: less than 36% of total tax paid — interest on shortfall to 45% of tax (3-month interest)
- By 15 December: less than 75% of total tax paid — interest on shortfall to 75% of tax (3-month interest)
- By 15 March: less than 100% of total tax paid — interest on shortfall to 100% of tax (1-month interest)
The 12% / 36% / 75% / 100% test at the first three dates is a safe harbour — if you meet that lower threshold (instead of 15% / 45% / 75% / 100%), no 234C interest for that instalment. The full 15% / 45% / 75% / 100% is the “ideal” track.
The capital-gains / dividend carve-out
The proviso to Section 234C provides an important relief: if the shortfall is on account of capital gains or dividend income that arose after a particular advance-tax due date, the 234C interest is not charged on that portion — provided the tax on that income is paid in the next instalment.
Example: you sell a property on 30 November producing Rs 10 lakh of LTCG, with tax thereon of Rs 1.25 lakh. The 15 September instalment has passed and you couldn’t have known about this gain on 15 June or 15 September. As long as you pay the additional Rs 1.25 lakh by 15 December (the next instalment after the gain arose), no 234C on the LTCG portion. If you defer it to 15 March, you incur 234C on the December instalment shortfall.
The carve-out also applies to dividends declared / received after a given instalment date. Critically, it does not apply to salary, business or other income types that should have been foreseeable at each instalment.
How 234B and 234C interact
234B and 234C are independent — both can apply to the same taxpayer in the same year. 234C captures the timing of within-year instalments; 234B captures the end-of-year shortfall (if total advance tax + TDS < 90% of assessed tax).
Common pattern: salaried taxpayer with rental + capital-gains income who pays no advance tax through the year, relies only on salary TDS. At year-end the TDS covers less than 90% of total tax. Both 234B and 234C are triggered. 234C covers the four missed instalments (cumulative); 234B covers the post-March-end period until self-assessment tax is paid.
How to avoid both
- Estimate the full-year tax in May / June. Take last year’s tax as a baseline, adjust for known changes (slab, regime change, expected investment income, planned property sale, etc.).
- Track TDS and TCS already deducted at source via Form 26AS / AIS. The 90% threshold is on the gap, not on the total.
- Pay the first instalment by 15 June — at least 15% of the estimated liability.
- Re-estimate quarterly. By 15 September re-check actuals against forecast and pay the cumulative 45%.
- Treat large capital events (property sale, equity exit, dividend declaration, ESOP exercise) as their own mini-instalment in the next due date.
- The 15 March instalment is the hardest to estimate because the financial year is not over — use the most-accurate-available estimate of the year’s income and pay 100%.
What happens when you miss
The interest is automatic in the ITR processing. The e-filing portal computes 234B / 234C based on the advance-tax challans on record and the assessed tax in the return. There is no “reasonable cause” waiver in 234C (unlike penalty provisions); it is a charge, not a penalty. 234B has a long-standing position that it survives even if the assessed tax is later reduced on appeal — the interest is on the period the tax was outstanding, not on the final assessed amount.
The senior-citizen exemption
Senior citizens (60 years or older during the previous year) with no income chargeable under “Profits and gains of business or profession” are exempt from advance-tax under Section 207(2). Practical impact: a retiree with only pension, FD interest, dividend and capital gains pays no advance tax. The full liability can be settled as self-assessment with the ITR. Neither 234B nor 234C applies to such an assessee.
The exemption falls away the moment the assessee has any business income — even small consulting fees that are reported as business income trigger the full advance-tax regime.
Sources
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