A SIP return calculator answers the single most important question every mutual-fund investor asks: if I invest ₹X per month for Y years, what will I have at the end? This guide explains the formula behind the number, shows realistic return assumptions across fund categories, and covers the two things most SIP return calculators quietly ignore: inflation and LTCG tax.
How a SIP Return Calculator Works
Every honest SIP return calculator uses the future-value-of-annuity formula. Each monthly SIP contribution compounds for the remaining months of your tenure — the first month's ₹5,000 gets full n months of compounding, the last month's ₹5,000 gets just one.
where:
P = monthly SIP amount
r = monthly return = annual rate ÷ 12
n = number of months
For a ₹10,000 monthly SIP at 12% annual returns over 20 years: r = 0.01, n = 240, and the formula gives you approximately ₹99.9 lakh. Half of that is what you invested; the other half is compound returns.
Realistic SIP Return Rates by Fund Category
The "12%" assumption you see everywhere applies to equity funds over long periods (10+ years). Different fund types have historically delivered different ranges:
| Fund Category | Historical CAGR (10-yr) | Risk | Best For |
|---|---|---|---|
| Large-Cap Equity | 10–13% | Moderate | Stable long-term growth |
| Flexi-Cap / Multi-Cap | 11–14% | Moderate-High | Balanced equity exposure |
| Mid-Cap / Small-Cap | 13–18% | High | Aggressive, 10+ year horizon |
| ELSS (Tax-Saver) | 11–14% | Moderate-High | 80C + long-term wealth |
| Hybrid / Balanced | 9–12% | Moderate | Moderate risk investors |
| Debt Funds | 6–8% | Low | Short-term goals, capital preservation |
Historical returns are not guarantees. To stress-test any SIP return calculator's number, run it at three rates — an optimistic (14%), a realistic (12%), and a pessimistic (8%) — and plan against the pessimistic outcome.
SIP Return Calculator: Common Scenarios
Here's what different monthly SIPs would grow to at 12% CAGR (equity long-term average), if the assumption holds:
| Monthly SIP | 10 years | 15 years | 20 years | 25 years |
|---|---|---|---|---|
| ₹5,000 | ₹11.6 L | ₹25.2 L | ₹50.0 L | ₹95.0 L |
| ₹10,000 | ₹23.2 L | ₹50.5 L | ₹99.9 L | ₹1.90 Cr |
| ₹15,000 | ₹34.8 L | ₹75.7 L | ₹1.50 Cr | ₹2.85 Cr |
| ₹25,000 | ₹58.0 L | ₹1.26 Cr | ₹2.50 Cr | ₹4.74 Cr |
| ₹50,000 | ₹1.16 Cr | ₹2.52 Cr | ₹5.00 Cr | ₹9.49 Cr |
The take-away: doubling your monthly SIP doubles your final corpus. But doubling your tenure roughly triples it because compounding accelerates in the later years. Starting early beats investing more later, most of the time.
What Most SIP Return Calculators Get Wrong
1. They show nominal returns, not real returns
Your ₹99.9 lakh at year 20 sounds huge — but at 6% inflation, that has the purchasing power of roughly ₹31 lakh in today's rupees. When you plan a goal (₹1 crore for retirement, ₹50 lakh for education), the goal is in today's money. So either inflate the goal or discount the calculator's output:
Our Lumpsum Calculator shows both nominal and inflation-adjusted values — use it as a mental model for how much your SIP corpus is really worth.
2. They ignore LTCG tax
Since Budget 2024, equity mutual fund gains above ₹1.25 lakh per financial year are taxed at 12.5% LTCG. On a ₹50 lakh corpus with ₹35 lakh gain, roughly ₹4.2 lakh goes to tax — so plan for around 8–9% of your gains being trimmed at withdrawal, not zero.
Debt funds are worse: taxed at your income slab rate (no indexation for units bought after April 2023). If you're in the 30% bracket, that's a big drag on debt-fund SIP returns.
3. They assume you never stop
A 20-year projection assumes you keep depositing every single month, through every market crash, salary loss and life event. Real investors pause SIPs on average 3–4 times in a 20-year run. Model your SIP return with that in mind — either use conservative assumptions, or set up an annual step-up that offsets missed months in later years.
SIP Return vs Fixed Deposit — The Real Post-Tax Comparison
People compare a 12% SIP return to a 7% FD return and see 5% extra. Post-tax, the gap is smaller than that: a 12% equity SIP after LTCG works out to roughly 10.5% effective. A 7% FD, taxed at 30% slab, is only 4.9% effective. So the real gap is closer to 5.6%, not the raw 5% headline. See our SIP vs Fixed Deposit calculator for the full side-by-side.
How to Actually Use a SIP Return Calculator
- Start with the goal, not the SIP amount. "I want ₹1 crore in 20 years in today's money" — inflated at 6%, that's ₹3.2 crore nominal. Now solve for the SIP.
- Run three return scenarios (8%, 10%, 12%). Plan against the middle.
- Add a 10% step-up. Match your SIP increment to your annual salary hike. Uses our Step-Up SIP Calculator.
- Subtract LTCG tax from the target. Aim for goal + ~10% buffer.
- Re-check every year. Life, income, and markets all change; your assumptions should too.
Ready to run your numbers? Try our main SIP calculator for a monthly SIP projection, or the Step-Up SIP Calculator if you want to model annual increments.