What is a SIP Calculator?

A SIP calculator is a tool that answers one question: if I invest a fixed amount every month, what will it be worth at the end? It runs a future-value-of-annuity calculation — your monthly amount, an assumed monthly rate of return, and the number of instalments. Those three inputs are the whole model.

How to use it

1. Monthly amount — what you can genuinely commit every month, not an aspirational figure.
2. Expected return — 10–12% is defensible for equity funds over long horizons, 8–10% for hybrid, 6–7% for debt.
3. Tenure — the input that matters most. Add five years before you add ₹2,000.
4. Read the split — the gap between what you invested and the final corpus is the compounding, and it only overtakes your contributions around year eleven.

What return should you assume?

Twelve percent is the internet’s default and it deserves scrutiny. It loosely reflects long-run Indian equity index returns, but individual years have ranged from roughly −25% to +40%. Set the slider to 8% and the 15-year corpus on a ₹10,000 SIP falls from about ₹50.4 lakh to roughly ₹34.6 lakh — same discipline, same ₹18 lakh contributed, ₹16 lakh less at the end. The assumption is not a footnote.

Where this maths quietly breaks

• Returns aren’t smooth. The formula assumes a steady monthly rate. Markets don’t supply one, and the order in which good and bad years arrive changes your outcome.
• Inflation. ₹50 lakh in 15 years won’t buy what ₹50 lakh buys today — at 6% inflation, closer to ₹21 lakh in today’s money.
• Tax. Long-term capital gains on equity funds are taxed above the annual exemption. The figure shown is pre-tax.
• Expense ratio. A 1.5% regular plan against a 0.5% direct plan costs several lakh over 15 years, silently.

Common questions

Can I change my SIP amount midway?

Yes. You can increase, decrease, pause or stop a SIP at any time — it’s a standing instruction, not a contract. A step-up SIP that rises 10% a year turns a 15-year ₹10,000 SIP from roughly ₹50.4 lakh into around ₹80 lakh, which makes it the highest-leverage change available if your income is growing.

Is the result guaranteed?

No. It’s a projection built on an assumed rate, not a forecast. Treat it as a planning aid for comparing scenarios, not a promise of a number.

What is rupee-cost averaging?

Because you invest a fixed rupee amount each month, you automatically buy more units when prices are low and fewer when prices are high. Over a long enough period this smooths out your average purchase price and removes the need to time the market.

What happens if I miss a month?

Nothing punitive from the fund — it simply doesn’t buy units that month. Your bank may charge a mandate-failure fee. One miss in 180 instalments is statistically irrelevant; a habit of missing them is not.