SIP vs Fixed Deposit: How Each One Actually Works

Updated: 2 September 2026

A fixed deposit gives you a number the bank has committed to. A SIP gives you a number you assumed. Both often turn up in the same sentence — "7% versus 12%" — and that comparison is the most misleading thing about the pair. Here is what actually differs.

What a fixed deposit is

You place a sum with a bank for an agreed term at an interest rate fixed when you open the deposit. At the end of the term you get the money back with interest, and the rate does not move even if markets do. Other countries call the same structure a term deposit or a certificate of deposit.

What a SIP is

A systematic investment plan is not a product — it is a schedule. You put a fixed amount into a market-linked fund at regular intervals, usually monthly, and each instalment buys units at whatever that day's price is. Because the amount stays fixed while the price moves, you buy more units when prices are low and fewer when they are high, which averages out your purchase price. That smooths what you pay; it does not guarantee a gain.

The differences that matter

• Certainty. An FD's return is contractual. A SIP's is not: your units can be worth less than the total you put in, especially over short periods.
• Who carries the risk. With an FD the bank owes you a defined amount, and many countries run deposit insurance covering balances up to a limit that differs by country, so check yours. With a SIP you carry the market risk yourself, and nobody owes you a return.
• Liquidity. Breaking an FD early is usually allowed but typically costs a penalty and a reduced rate. Fund units can usually be sold on any business day, but at the prevailing price — which may be below what you paid — and some funds charge an exit fee early on.
• Tax. Rules differ by country and over time, so no article can give you the number. Deposit interest and investment gains are often taxed under different rules and at different moments: interest as it is earned, gains when you sell. Check your country's current rules, or a tax adviser.
• Costs. An FD's quoted rate is what you receive. A fund deducts an ongoing expense ratio before any return reaches you.

Why the headline rates are not comparable

1. One is promised, the other assumed. The FD rate is what the bank agreed to pay. The SIP figure is whatever you typed in — often a fund's past average, which nobody has committed to repeating.
2. The cash flows differ. An FD is normally one deposit sitting for the term. A SIP is many small deposits, each invested for a different length of time — the final instalment for only a month. The two maturity values therefore describe different amounts held for different durations. The bank product with SIP-shaped cash flow is a recurring deposit, not an FD.
3. A single rate hides the range. Markets do not repeat one return every year. An honest SIP projection is a range of outcomes, including poor ones, not one tidy figure.

Who tends to use which

Money that has to be a specific amount on a specific date — next year's fees, a deposit, an emergency buffer — tends to go where the amount is known. Money with a long horizon, held by someone able to sit through falls in value, is where people accept market risk for higher potential growth. Plenty of people run both at once, for different goals. There is no universal split, and no article can pick for you.

Testing both, honestly

The FD Calculator and SIP Calculator apply standard compounding formulas to the figures you enter; the arithmetic is currency-neutral, so amounts work in any currency. Use them to explore, not to decide: run the SIP calculator at two or three rates, including a deliberately pessimistic one, and match the cash flows before comparing results. Neither includes tax, fees or fund expenses, so each figure is an illustration, not a forecast, and none of this is financial advice. Check anything affecting a real decision with your bank, fund provider or a qualified adviser.