SIP Calculator

Estimate the future value of your monthly SIP investment.

What a SIP calculates

A systematic investment plan invests a fixed amount at regular intervals. Because each instalment compounds for a different length of time, the maturity value is the sum of a series rather than a single compounding calculation.

M = P x ((1 + i)^n - 1) / i x (1 + i)

M = maturity value   P = monthly investment
i = monthly return (annual / 12 / 100)   n = number of months

A worked example

Investing 10,000 a month for 15 years at an assumed 12% annual return:

Your first instalment compounds for 180 months; your last compounds for one. That spread is why the early years matter so disproportionately.

Time dominates everything

DurationInvestedValue at 12%Gain
5 years600,000826,000226,000
10 years1,200,0002,323,0001,123,000
15 years1,800,0005,046,0003,246,000
20 years2,400,0009,991,0007,591,000
25 years3,000,00018,976,00015,976,000

10,000 monthly. Doubling the duration from 10 to 20 years doubles the money invested but multiplies the final value more than fourfold. Starting five years earlier is worth more than increasing the instalment substantially — which is the single most useful thing this table shows.

Rupee cost averaging

A fixed monthly amount buys more units when prices are low and fewer when high, which lowers the average cost per unit compared with the average price over the period. This is the mechanical benefit of investing regularly, and it removes the need to judge market timing.

It is worth being accurate about what this does and does not do. It reduces the risk of committing everything at a market peak, and it makes investing a habit rather than a decision. It does not guarantee a profit and does not protect against a sustained decline. Research generally finds that lump-sum investing outperforms staged investing on average, simply because markets rise more often than they fall — the case for a SIP is behavioural and practical rather than mathematical.

The return assumption is not a promise

This is the most important limitation. The calculation assumes a constant annual return, and no market delivers that. Equity returns arrive unevenly: a period might produce 12% on average through years of +30%, -15% and +22%.

The order matters too. Two investors earning the same average over the same period can end up with different amounts, because a poor sequence early in an accumulating portfolio has a different effect from a poor sequence late. Run the calculation at several rates — 8%, 10%, 12% — to see how sensitive your plan is, and treat the range as the answer rather than any single figure.

Inflation, tax and fees

Step-up SIPs

Increasing the instalment annually in line with income has a substantial effect. A 10,000 SIP growing 10% a year over 15 years at 12% reaches roughly 8,700,000 against 5,046,000 for a flat one — a 72% improvement for contributions that stay constant as a share of a rising income. Most platforms support this automatically.

Frequently asked questions

Is the 12% return guaranteed?

No. It is an assumption, and market returns vary year to year and can be negative. Run the calculation at 8%, 10% and 12% and treat the spread as the realistic range rather than relying on a single figure.

Is a SIP better than investing a lump sum?

On average, lump-sum investing outperforms, because markets rise more often than they fall. A SIP's advantages are behavioural — it removes timing decisions, builds a habit, and limits the regret of investing everything at a peak.

Does this account for inflation?

No, the result is in nominal terms. At 6% inflation, money loses roughly half its purchasing power over 12 years. Subtract inflation from your assumed return for a real-terms estimate.

What is a step-up SIP?

One where the monthly amount increases annually, usually in line with income. Increasing a 10,000 SIP by 10% a year for 15 years at 12% produces around 8,700,000 against 5,046,000 for a flat contribution.

How much difference does the expense ratio make?

More than most people expect. A one percentage point difference in annual fees costs roughly 15% of the final corpus over 20 years, because the fee compounds against you every year alongside the returns.

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