SIP Calculator — See How Your Monthly Investment Grows Over Time

By sadiqbd · June 6, 2026

A SIP is the simplest wealth-building tool most people ignore

The pitch for a SIP (Systematic Investment Plan) is almost suspiciously simple: invest a fixed amount every month in a mutual fund, keep going for years, and let compounding do the work. No timing the market, no complex strategy, no need to monitor constantly. Just consistency.

What most people don't have is a clear picture of what that consistency actually produces. "It grows over time" isn't satisfying when you're deciding whether to commit ৳5,000 a month for the next 15 years. A SIP calculator replaces the vagueness with actual numbers — here's what ৳5,000 per month at 12% annual return over 15 years actually becomes, and here's how much of it is your money vs. market growth.

How SIP Returns Are Calculated

A SIP works differently from a lump sum investment. Each monthly instalment is invested at that month's NAV (net asset value), earns returns for the time remaining until the end of the investment horizon, and compounds forward. Because instalments are made monthly, the first instalment compounds for the full tenure, the second for one month less, and so on.

The formula for SIP maturity value:

M = P × [((1 + r)^n − 1) / r] × (1 + r)

Where:

M = maturity amount
P = monthly SIP amount
r = monthly return rate (annual rate ÷ 12)
n = number of monthly instalments

For P = ৳5,000, annual return = 12%, n = 180 months (15 years):

r = 12% ÷ 12 = 1% per month = 0.01
M = 5,000 × [((1.01)^180 − 1) / 0.01] × 1.01
M ≈ ৳25,22,880

Total invested: ৳5,000 × 180 = ৳9,00,000 Total returns: ৳16,22,880 — more than the total amount invested.

That's the compounding effect of 15 years. Your money nearly triples, and the growth exceeds your total contribution.

How to Use the SIP Calculator on sadiqbd.com

Enter your monthly SIP amount — start with whatever you can realistically commit to every month without fail. Even ৳1,000 adds up.
Enter the expected annual return — mutual fund returns vary. Equity funds have historically returned 10–15% over long horizons in South Asian markets, though past performance doesn't guarantee future results. Use 10–12% for conservative projections; 12–15% for optimistic ones.
Enter the investment duration — in years. The longer the horizon, the more dramatic the compounding effect.
Read the result — the calculator shows total invested amount, estimated returns, and total maturity value. The gap between invested and maturity value is your wealth creation.

Real-World Examples

Young professional starting at 25

Fahmida starts a ৳3,000/month SIP at 25 in a diversified equity fund targeting 12% annual returns. She plans to continue until 55 — 30 years.

Total invested: ৳10,80,000
Maturity value at 12%: ≈ ৳1,05,18,000 (over ৳1 crore)
Wealth created: ≈ ৳94,38,000

She invested less than ৳11 lakh and accumulated over ৳1 crore. The 30-year horizon and consistent 12% return do nearly all the work. Starting at 25 instead of 35 with the same amount roughly triples the outcome.

Mid-career professional at 38

Shaheen starts at 38 with ৳10,000/month at 11% annual return for 22 years (retiring at 60).

Total invested: ৳26,40,000
Maturity value: ≈ ৳1,02,57,000
Wealth created: ≈ ৳76,17,000

A higher monthly contribution and a longer horizon still gets him past ৳1 crore, despite starting later. The lesson: starting later requires more monthly commitment to reach similar outcomes.

Comparing SIP amounts side by side

Three friends start SIPs at 30 for 25 years at 12%:

Friend A: ৳2,000/month → maturity ≈ ৳37,98,000
Friend B: ৳5,000/month → maturity ≈ ৳94,95,000
Friend C: ৳10,000/month → maturity ≈ ৳1,89,90,000

The maturity amounts scale linearly with the SIP amount (as expected), but all three show the same compounding multiplier — about 6.3x the total invested at 12% over 25 years. The calculator makes this multiplier visible.

SIP vs. lump sum comparison

Someone has ৳1,20,000 available. They're deciding between:

Lump sum: ৳1,20,000 invested today at 12% for 10 years → ≈ ৳3,72,756
SIP: ৳10,000/month for 12 months, then left to grow for 9 more years

For the SIP route: the 12 monthly instalments grow to roughly ৳1,27,000 by end of year 1, then compound at 12% for 9 more years → ≈ ৳3,31,000

The lump sum slightly outperforms when invested early — it compounds from day one. The SIP spreads the investment over 12 months, so average cost is 6 months into the year. For volatile markets, SIPs can outperform lump sums through rupee cost averaging; for trending markets, lump sums tend to win.

Why SIP Beats Trying to Time the Market

The most common reason people delay starting a SIP is that they're waiting for the "right time" — a market dip, a correction, a better entry point. This almost always results in not starting at all.

SIPs make the timing question irrelevant through rupee cost averaging. When markets are high, your ৳5,000 buys fewer units. When markets fall, the same ৳5,000 buys more units at a lower price. Over time, this averaging smooths out market volatility and typically results in a lower average cost per unit than trying to time individual purchases.

The real risk isn't buying when the market is slightly high — it's not investing at all while waiting for perfect conditions that rarely arrive.

Tips for Getting More From Your SIP

Increase your SIP amount annually. Even a 10% step-up each year dramatically changes your long-term outcome. A ৳5,000 SIP increasing by 10% annually for 20 years produces roughly 40% more than a flat ৳5,000 SIP — because your later years have much higher monthly amounts compounding forward.

Don't stop during market downturns. Volatility is the point at which SIPs generate the most benefit — you're buying more units at lower prices. Stopping when markets fall locks in losses and misses the recovery. The instinct to pause is usually the worst time to act on it.

Separate SIPs for separate goals. Rather than one large SIP for "everything," run distinct SIPs for retirement, a child's education, and a property purchase with different horizons and fund choices. This makes goal tracking clear and prevents premature withdrawal for the wrong reason.

Use a direct plan, not a regular plan. If investing through a mutual fund platform, direct plans have no distributor commission — this saves 0.5–1% in expense ratio annually. Over 15–20 years, that percentage compounds into a meaningful amount.

Treat the SIP amount as non-negotiable. Set up auto-debit and treat the SIP like a fixed expense — not a discretionary saving. The months you'd most want to skip (cash is tight, market is down) are often the most valuable months to stay invested.

Frequently Asked Questions

Is 12% annual return from a SIP realistic? Over long horizons (10–20+ years), diversified equity mutual funds in South Asian markets have historically delivered 10–15% annual returns. Over shorter periods, returns are far more variable and can be negative. Use 10% for conservative projections and 12% for moderate ones — and remember these are estimates, not guarantees.

What's the minimum SIP amount? Most mutual funds allow SIPs starting at ৳500 or ৳1,000 per month. There's no compelling reason to delay starting because the amount feels small — starting small and increasing over time consistently beats waiting to start large.

Can I pause or stop a SIP? Yes — SIPs can usually be paused for 1–3 months or stopped at any time without penalty. Your existing invested units continue to grow. Pausing occasionally for genuine cash flow reasons is fine; chronic stopping and starting defeats the purpose.

How is SIP return different from fixed deposit return? An FD offers guaranteed returns at a fixed rate. A SIP in an equity mutual fund offers market-linked returns — potentially higher over long periods, but not guaranteed and volatile in the short term. SIPs are suitable for goals at least 5 years away; FDs are better for shorter, fixed-horizon goals.

Is the SIP calculator free? Yes — free to use, no account needed, unlimited calculations.

A SIP is not a shortcut to wealth — it's a long game played consistently. The calculator shows you what that game actually pays off. The numbers are usually more encouraging than people expect, which is often the push needed to stop planning and start investing.

Try the SIP Calculator free at sadiqbd.com — see what your monthly investment grows to, and start with a number you can sustain.