SIP calculator guide: monthly investment, returns and risks

How does a SIP calculator work?

A Systematic Investment Plan (SIP) is a way to invest a chosen amount in a mutual fund at regular intervals, often monthly. A SIP calculator helps you estimate what the series of investments might be worth after a chosen period using an assumed rate of return.

It does not tell you which fund will perform best, whether you will make a profit or what the market will do next. SEBI's own SIP calculator explicitly says its results are illustrations and that stock-market returns cannot be predicted.

Try the SIP Calculator on Janooji to experiment with your own contribution and duration.

What numbers should you enter?

You generally need three inputs:

• SIP amount: the money invested at each interval, such as ₹2,000 or ₹5,000 per month.
• Investment duration: how many months or years you plan to continue.
• Expected annual return: an assumption for the projection, *not* a forecast or promised interest rate.

If you invest ₹5,000 every month for ten years, your total contributions are ₹6,00,000 (₹5,000 × 120 months), before gains, losses, charges or other adjustments. The calculator's estimated future value is a separate number determined by its compounding assumptions.

Try multiple plausible scenarios rather than relying on one optimistic percentage.

Why do SIP estimates differ across calculators?

Different calculators can assume contributions happen at the start or end of a month and may convert annual to monthly growth using different conventions. Some include or omit expenses, taxes, step-up contributions and irregular investment dates.

Two calculators can therefore show slightly different estimates for the same monthly amount, years and assumed percentage without one necessarily being broken. Look at the model and assumptions before treating the output as a precise maturity figure.

SIP returns are not bank FD interest

An FD normally has a contracted deposit rate for the stated term under its product conditions; mutual fund units instead have a net asset value (NAV) that moves with investments held by the fund. Investing through SIP does not change that market risk.

When prices fall, a fixed rupee contribution can buy more units; when prices rise, it buys fewer. This is commonly called rupee-cost averaging, but it does not guarantee profits or eliminate losses.

For a deposit-style projection instead, use the FD Calculator, remembering that the two products have very different risk profiles.

Estimated return versus actual return

An SIP projection is based on a *chosen* constant growth assumption. An actual investor's return depends on how much went in, when each instalment went in, whether instalments were skipped, the value of the fund and any withdrawals.

For performance on transactions occurring on different dates, investors may encounter the measure called XIRR, which annualises the return of an irregular cash-flow series. The future-value number in a simple SIP calculator is not the same thing as your fund's realised XIRR.

A practical way to use the estimate

1. Decide an amount you can afford to invest without disrupting essential expenses. 2. Enter the actual intended time horizon. 3. Test a conservative, middle and optimistic assumed return, including a low or negative scenario where supported. 4. Compare amount invested against estimated future value. 5. Revisit assumptions rather than treating any projection as a target you are entitled to receive. 6. Check the fund's risk label and official disclosures before choosing a product.

Mutual funds involve market risk and past performance does not predict future returns. This guide explains the calculation, not a recommendation to buy any particular fund.

Related tool: Janooji SIP Calculator.