The 8th wonder of the world, visualised. See your money multiply — compare rates, compare years, and discover how compounding frequency changes everything.
CI = P(1 + r/n)ⁿᵗ + monthly SIP
SI = P × R × T / 100
A = P(1 + r/n)^(nt). P = principal, r = annual rate, n = compounds per year, t = years. Your interest earns interest — the snowball effect that builds generational wealth.
A Systematic Investment Plan (SIP) adds a fixed amount monthly. Over 20 years, a ₹5,000/month SIP at 12% builds ~₹50 lakh. A lump sum of ₹6L at the same rate builds ~₹58L — similar outcome, different risk profile.
The annualised return of an investment. Nifty 50 CAGR: ~12% over 20 years. FD CAGR: 6.5–7.5%. CAGR smooths volatility — actual year-by-year returns vary significantly from this average.
72 ÷ interest rate = years to double. At 6%: 12 years. At 9%: 8 years. At 12%: 6 years. This mental shortcut works within ±1 year for rates between 5–20%. Used by Warren Buffett as a quick valuation check.
Nominal return minus inflation = real return. A 10% FD during 6% inflation gives a real return of only ~4%. Equity mutual funds targeting 12% nominal at 6% inflation deliver ~6% real wealth growth.
Monthly vs annual compounding on ₹1L at 8% for 10 years: monthly gives ₹2,21,964 vs annual ₹2,15,892 — a difference of ~₹6,000. More frequency = slightly more — but rate matters far more than frequency.
My uncle Venkatesh worked as a government clerk in Coimbatore for 35 years. He never earned more than ₹40,000 a month. But when he retired at 60, he had a corpus of ₹1.2 crores. His secret wasn't a high salary or a stock market windfall — it was a PPF account he opened at 25 and never touched, a ₹2,000 monthly SIP he started in 1998 when SIPs weren't even fashionable, and the stubborn discipline of reinvesting every dividend and interest payment. He didn't know the formula for compound interest. He just understood one thing: money that stays invested makes more money, which makes more money, which makes more money.
That invisible multiplication is compound interest — and this calculator makes it visible. Enter your principal, monthly SIP, interest rate, and tenure. See the exact rupee amount your money becomes, compare what different rates produce, watch how starting 5 years earlier changes everything, and understand why Albert Einstein reportedly called compound interest the eighth wonder of the world.
Compound interest is interest calculated on both the original principal and the accumulated interest from previous periods. In simple terms: your interest earns interest. This creates an exponential growth curve — slow at first, then dramatically accelerating in later years — which is why long investment horizons are so powerful.
Compare this with simple interest, where you earn the same flat amount every year on your original principal only. At 8% simple interest, ₹1 lakh earns ₹8,000 every single year for 20 years — total interest: ₹1,60,000. At 8% compound interest (monthly), the same ₹1 lakh earns ₹3,86,968 over 20 years — more than double. The difference isn't magic. It's just time multiplied by reinvestment.
Six inputs, endless insight. Here's what each field means:
Choose your local currency. For INR, a live RBI benchmark panel appears showing current PPF (7.1%), SCSS (8.2%), FD rates (6.5–7.5%), and equity MF historical returns (~12%). For USD, UK GBP, EUR, and JPY — country-specific rate benchmarks and tax wrappers (401k, ISA, NISA) auto-load in the advice panel.
Your starting lump sum — could be ₹10,000 or ₹10,00,000. If you're starting from scratch with only monthly contributions, enter 0 here and set your monthly SIP below. The calculator handles both lump sum, SIP-only, and combined strategies.
The fixed amount you add every month. Even small amounts compound into large sums — ₹3,000/month at 12% for 25 years grows to approximately ₹57 lakhs. Try different SIP amounts to find the minimum monthly investment needed to reach your target corpus.
Use benchmarks from your region. India: PPF 7.1%, bank FD 7–7.5%, equity MF historical 12%, NPS ~10%. US: S&P 500 historical 10%, HYSA 4.5%. The rate comparison table automatically generates results for 6 nearby rates so you can see what a 1% difference actually means in rupees over your tenure.
Years: how long you'll stay invested. Compounding frequency: how often interest is calculated and added to principal — daily, monthly, quarterly, semi-annual, or annually. Monthly is most common for SIPs and mutual funds. The frequency comparison table shows you the exact rupee difference between options.
You'll get: final balance and growth chart, a rate comparison table (what 1–3% more or less means over your tenure), a years comparison table (5yr to 30yr milestones), a compounding frequency comparison, and a full year-by-year schedule. Use the "Convert to USD" button for global NRI comparisons.
Quick example: ₹1,00,000 at 8% compounded monthly for 10 years: A = 1,00,000 × (1 + 0.08/12)^(12×10) = ₹2,21,964. Total interest earned = ₹1,21,964. Your money more than doubled without adding a single rupee extra.
Divide 72 by your interest rate to find years to double your money. At 8%: 72÷8 = 9 years. At 12%: 72÷12 = 6 years. At 6%: 12 years. This mental shortcut works within ±1 year for rates between 5–20%. Warren Buffett uses it for quick valuation checks.
CAGR = (Final Value / Initial Value)^(1/years) − 1. This is the annualised return that smooths out year-to-year volatility. Nifty 50 CAGR over 20 years: ~12%. FD CAGR: 6.5–7.5%. Use CAGR to compare investments with different tenures on equal terms.
Ananya starts a ₹5,000/month SIP at age 25 into a Nifty 50 index fund at 12% CAGR. Her twin brother Arun waits until 35 to start the same ₹5,000/month at the same rate. Both invest until age 60. Ananya accumulates ₹3.24 crore. Arun accumulates ₹1.76 crore. Ananya invested ₹18 lakhs more in total contributions, but ends up with ₹1.48 crore more at retirement. The 10-year head start — not higher contributions, not better stock picks — is the entire reason. This calculator's year comparison table will show you your own version of this story.
Ramesh has ₹5 lakhs to invest. His bank manager recommends a 15-year FD at 7.5%. His friend suggests a Nifty index fund averaging 12%. Both compound monthly. FD at 7.5%: ₹5L becomes ₹15.46L. Index fund at 12%: ₹5L becomes ₹27.37L. The 4.5% rate difference produces an extra ₹11.91 lakhs on the same ₹5 lakh investment — without touching it. Use the rate comparison table in this calculator to see exactly what rate differences mean for your specific investment amount and timeline before making your decision.
Priya spends ₹200/day on chai, snacks, and impulse Swiggy orders — about ₹6,000/month she never tracks. Her colleague Nisha redirects the same ₹6,000/month into an ELSS fund at 12%. After 20 years, Nisha has ₹59.97 lakhs. Priya has the memory of 7,300 cups of chai. This isn't about never enjoying chai — it's about making the compounding math visible. When you know ₹200/day is worth ₹60 lakhs in 20 years, you make different choices. Use the monthly contribution field: enter 6000, set 20 years, 12% — and see your own "chai number."
Vikram is an NRI in the US deciding where to invest $10,000. Option A: India PPF at 7.1% (tax-free, INR). Option B: S&P 500 index fund at 10% historical average (USD). He uses this calculator in INR mode for PPF, then USD mode for S&P 500, then hits "Convert to USD" to compare on equal terms. At 15 years: PPF equivalent ~$23,100 | S&P 500 ~$41,770. The 2.9% annual rate gap becomes a $18,670 difference — but he also considers currency risk, India's tax-free status, and the guaranteed nature of PPF vs equity volatility. The numbers are now clear; the decision is his.
Rate, principal, and SIP amount can all be improved later. Time cannot. Every year you delay starting means your final corpus is permanently smaller — no amount of catching up fully compensates. Starting with ₹1,000/month today beats starting with ₹3,000/month in 5 years, in most 20+ year scenarios.
Withdrawing or redeeming investments early resets the compound curve. A ₹1 lakh investment at 12% that you withdraw after 10 years (₹3.1L) and then reinvest for another 10 years earns far less than leaving it untouched for 20 years (₹9.6L). Every interruption is expensive. Name your goal, match the tenure, and don't touch it.
A 1.5% annual fund expense ratio on a 12% return doesn't cut your returns by 12.5% — it cuts them by much more over time due to compounding. ₹10L at 12% for 20 years: ₹96.4L. At 10.5% (1.5% fee): ₹73.7L. The fee costs ₹22.7 lakhs — more than twice the original investment. Always check expense ratios. Direct mutual funds in India have 0.1–0.5% vs regular plan's 1–2%.
Using 15% or 18% in your calculations while investing in FDs or debt funds is dangerous fantasy planning. FDs: 6.5–7.5%. PPF: 7.1%. Balanced funds: 9–10%. Nifty index (equity): 10–12% historical, with real possibility of 0% or negative in any single year. Plan with conservative rates; be pleasantly surprised if you beat them.
FD interest in India is taxed at your income slab rate — for someone in the 30% bracket, a 7.5% FD actually earns 5.25% post-tax. Equity LTCG is taxed at 12.5% above ₹1.25 lakh/year. PPF remains EEE (Exempt). ELSS qualifies for ₹1.5L 80C deduction. Always model post-tax returns. This calculator shows pre-tax — adjust your rate downward by your effective tax drag.
Most people set a ₹5,000/month SIP and never increase it. But if your income grows 10% per year, increasing your SIP by even 10% annually creates dramatically higher outcomes. ₹5,000/month flat for 20 years at 12%: ₹49.9L. ₹5,000 stepped up 10%/year: ₹1.37 crore. The step-up alone is worth ₹87 lakhs on the same initial commitment. This calculator doesn't model step-ups — do a separate calculation with your year-10 and year-20 SIP amounts.
Compound interest requires not touching your investment. But without an emergency fund, any unexpected medical bill, job loss, or major expense forces you to break the investment chain at the worst possible time — often during a market dip. Build your emergency fund first (3–6 months expenses in a liquid fund), then lock away your compound interest investment with the commitment to never touch it.
Compound interest works against you on debt. A credit card at 36% p.a. — which is effectively compounding monthly against you — will destroy any compounding gains from a 12% equity investment. Personal loans at 18–24% must be eliminated before serious investing begins. Only home loans at 8–9% (and car loans at similar rates) are debatable — in those cases, compounding investments alongside EMI can make sense if the investment rate exceeds the loan rate.
For guaranteed returns: PPF (7.1% fully tax-free EEE, 15-year lock-in) and SCSS (8.2% for senior citizens, taxable) are the safest. For moderate risk: NPS (10–12% historical equity allocation, with extra ₹50,000 tax deduction under 80CCD-1B). For long-term wealth: Nifty 50 or Nifty Next 50 index funds via SIP (12% historical CAGR, subject to market risk, LTCG taxed at 12.5% above ₹1.25L). For short-term parking: liquid mutual funds or short-duration debt funds (6.5–7.5%, better than FD post-tax for 30% bracket investors). There is no single "best" — the right option depends on your time horizon, tax bracket, liquidity need, and risk tolerance.
Simple interest (SI) = P × R × T / 100. Your interest is always calculated on the original principal only — no matter how many years pass, you earn the same flat amount each year. Compound interest (CI) = P × (1 + r/n)^(nt). Each year, interest is calculated on the previous year's total balance — including accumulated interest. The result: CI grows exponentially while SI grows linearly. On ₹1 lakh at 8% for 20 years: SI gives ₹2,60,000 total. Monthly compound interest gives ₹4,93,628 — almost double. The gap between them widens dramatically over longer time periods. Use the Simple Interest calculator on this page alongside the CI calculator to see the exact rupee difference for your numbers.
Less than most people think. The difference between monthly and daily compounding on ₹1 lakh at 8% for 10 years is only about ₹300–₹500. The difference between monthly and annual compounding is slightly larger — around ₹6,000 on ₹1 lakh over 10 years. So yes, more frequent is technically better, but the effect is minor compared to the impact of rate. Increasing your rate from 8% to 9% is worth roughly 10× more than switching from annual to daily compounding. Focus on finding better rates and investing more — not obsessing over compounding frequency. The frequency comparison table in this calculator shows the exact numbers for your investment.
It depends on rate and time. At 12% annual return (Nifty 50 historical average): to reach ₹1 crore in 20 years, you need approximately ₹10,000/month SIP. In 25 years: approximately ₹5,300/month. In 30 years: approximately ₹2,900/month. At 8% (FD/PPF): to reach ₹1 crore in 20 years, you need approximately ₹17,000/month. In 25 years: approximately ₹11,000/month. In 30 years: approximately ₹6,700/month. The lesson: time halves (or better) the required monthly contribution at the same rate. Use this calculator by setting the monthly SIP to trial amounts and adjusting until you find the number that hits ₹1 crore in your target years.
CAGR (Compound Annual Growth Rate) is the steady annual rate at which an investment would have grown if it grew at a uniform pace — essentially, the "annualised compound interest rate" of a real investment. Formula: CAGR = (Ending Value / Beginning Value)^(1/years) − 1. If a mutual fund grew from ₹1 lakh to ₹3.1 lakhs in 10 years, its CAGR = (3.1)^(1/10) − 1 = 12%. Real investments don't grow smoothly — they're up 20% one year, down 5% the next — but CAGR smooths that volatility into a single useful number for comparison. When fund houses advertise "12% CAGR since inception," they mean this compound annual rate — so entering 12% in this calculator is the correct way to project forward using their historical performance.
Your compound interest gains may be taxable — LTCG at 12.5%, FD interest as per slab. Find your actual after-tax return with country-specific tax brackets for India, USA, UK, Germany and France.
Estimate My Tax →Compound interest works against you on loans. See exactly how much interest you're paying on your home, car, or personal loan — and how extra payments can save you lakhs.
Calculate EMI →