SIP vs Fixed Deposit

The comparison most articles get wrong

Most SIP versus FD comparisons put a 12% equity assumption next to a 7% deposit rate, declare equity the winner, and stop. That is not a comparison, it is an assumption restated. The two products differ on three axes that all matter: the certainty of the return, the tax treatment of the gain, and what inflation does to each over the holding period.

Certainty is the honest advantage of a fixed deposit. The maturity value is contractual. You will receive it whether markets rose or fell, and for money you need on a known date within the next few years that is worth more than a higher expected return. An equity SIP offers no such promise: a five-year window can and does end below where it started.

Where tax changes the answer

Fixed deposit interest is taxable at your slab rate, in the year it accrues, whether or not you withdraw it. For someone in the 30% bracket, a 7% deposit returns roughly 4.9% after tax. If inflation is running near 6%, that is a real loss of purchasing power on money that felt safe.

Equity held beyond the long-term threshold is taxed more favourably, and only when you actually sell. That deferral matters: gains left invested keep compounding on the untaxed amount, which widens the gap over long horizons well beyond what the headline rates suggest.

This is why the post-tax column in the calculator above is the one to read. The pre-tax comparison flatters the deposit for lower earners and flatters equity for nobody in particular.

When a fixed deposit is genuinely the right answer

For an emergency fund, a deposit wins outright. The purpose of that money is to be available and intact on an unpredictable day, and volatility defeats both requirements.

The same applies to any goal inside about three years — a house deposit, a wedding, school fees. The expected return on equity is higher, but the distribution of outcomes over three years is wide enough that you could be forced to sell into a drawdown. Matching the instrument to the time horizon matters more than maximising the expected return.

And if a 20% paper loss would genuinely cause you to stop investing and sell, then your real return from equity is not the historical average. It is whatever you capture before you panic, which is usually considerably less. A deposit you hold beats an SIP you abandon.

When the SIP is the right answer

Over ten years and longer, the arithmetic strongly favours equity for money you will not touch. The volatility that makes equity unsuitable for a two-year goal is precisely what generates the premium over a long one, and monthly investing averages your purchase price across the cycle rather than betting on a single entry point.

Run both columns with your own numbers, then check the difference against what a fixed deposit leaves you after tax and inflation. For most long-horizon goals the gap is not marginal.