Advance Tax for Startups & Founders: Due Dates, Calculation & Penalties

Most first-time founders discover advance tax the hard way — a notice, an interest charge, or a chartered accountant asking in March why nothing was paid through the year. Advance tax is simply income tax paid in instalments as you earn, rather than in one lump at year-end. It applies to companies and to founders personally, the deadlines are fixed, and the penalty for ignoring it is automatic interest. Here's how it works and how to stay ahead of it.

What advance tax is

The Income Tax Act runs on a "pay as you earn" principle. If your total tax liability for the year is expected to be ₹10,000 or more after TDS, you're required to pay it in four instalments across the year instead of all at once. This applies to your Private Limited Company on its profits, and to you personally on income not fully covered by TDS — founder salary is usually covered by salary TDS, but consulting income, capital gains, interest, dividends and any business income taken directly are often not.

The four instalment deadlines

For most taxpayers, advance tax is due in four instalments each financial year, and the cumulative percentages are what matter:

• By 15 June — at least 15% of the estimated annual tax.
• By 15 September — at least 45% cumulative.
• By 15 December — at least 75% cumulative.
• By 15 March — 100% of the estimated annual tax.

These are cumulative targets, not equal quarters — by September you should have paid nearly half the year's tax, which surprises founders who assume it's spread evenly. Missing or underpaying an instalment doesn't just defer the problem; it starts the interest clock immediately.

The interest that makes ignoring it expensive

Two sections of the Act quietly penalise advance-tax slip-ups, and both apply automatically without any notice:

• Section 234C — interest for deferment, charged when you underpay any individual instalment. Miss the June or September target and interest accrues on the shortfall even if you catch up later.
• Section 234B — interest for default, charged when you've paid less than 90% of your total tax by year-end, running until you actually pay.

Both are charged at 1% per month. They're not enormous individually, but they're pure avoidable cost — money paid for nothing other than timing — and they compound the longer the underpayment sits. For a profitable company, a year of ignoring advance tax can turn into a meaningful interest bill on top of the tax itself.

Advance tax interest is the most avoidable line item in your P&L — it's a penalty purely for timing, not for owing.

How to estimate what you owe

The practical challenge is that advance tax requires you to estimate full-year income before the year is over. The method is straightforward: project your annual taxable income, compute the tax on it at applicable rates, subtract the TDS already being deducted on your behalf, and pay the balance across the four instalments. The obvious difficulty is that a startup's income can be lumpy and hard to forecast — a big contract or a one-off gain can move the number sharply. This is exactly where current, reliable books matter: you can only estimate accurately if you know your actual position through the year, which is one more reason monthly bookkeeping pays for itself. A good cash-flow model also helps you set aside the cash for each instalment rather than being caught short on the due date.

Special points founders miss

• Capital gains and dividends can't realistically be estimated in advance, so the law allows the advance-tax instalment for such income to be paid in the remaining instalments after the gain arises — but you must include it once it does.
• Presumptive taxation. Small businesses and professionals opting for presumptive schemes (44AD/44ADA) pay advance tax in a single instalment by 15 March, not four — a genuine simplification if you qualify.
• Founder vs company. Both can owe advance tax separately. Don't assume that because the company is paying, your personal liability on side income is covered — it isn't.
• Salary TDS isn't always enough. If you have income beyond a TDS-covered salary, the TDS won't cover your full liability, and the gap is yours to pay as advance tax.

How it fits the wider compliance calendar

Advance tax is one of several recurring deadlines that a founder juggling GST, TDS, payroll and ROC filings tends to forget precisely because it's quarterly and unprompted. The cleanest way to never miss it is to put all statutory dates on one compliance calendar with reminders and an owner, so the June and September instalments get the same attention as your monthly GST return. Our broader startup compliance checklist shows how advance tax sits alongside everything else you owe this year.

What to do if you've already missed an instalment

If you've underpaid a June or September instalment, the fix is to pay the shortfall as soon as possible — the interest keeps accruing until you do, so waiting for the next due date only adds cost. Then recalibrate your remaining instalments to hit the cumulative targets. It's not a filing you can revise; it's simply money owed, so the sooner it's paid the smaller the interest. Going forward, the answer is a proper estimate at the start of the year, revisited each quarter as actuals come in.

The bottom line

Advance tax isn't complicated, but it's unforgiving of neglect: fixed dates, cumulative targets, and automatic interest for underpayment. If your company is profitable or you have income beyond a TDS-covered salary, you almost certainly owe it — and paying it on schedule costs you nothing extra, while ignoring it costs 1% a month for no benefit. The two things that make it painless are an accurate income estimate (which needs current books) and a calendar that surfaces each instalment before it's due. If you'd like your advance tax estimated and tracked alongside your other filings, our compliance and accounting teams handle exactly this — get in touch before the next instalment date.