Every SIP calculator assumes 12%. Every lumpsum projection uses a smooth CAGR. Every financial plan bets on compounding working as promised. But does it? The Convergence Lab puts calculator assumptions against actual Nifty 50 data — year by year, month by month — and asks the only question that matters: when does projection become reality?
Walk into any mutual fund advisor's office and you will see it: the SIP calculator set to 12% CAGR, the lumpsum projection showing a clean exponential curve, the retirement plan built on assumptions that feel right but have never been tested against real market data.
The Convergence Lab exists to bridge this gap. Three tools, each attacking the same question from a different angle: lumpsum verification, SIP verification, and the time variable that makes it all work.
The answer is clear. Calculators are not wrong — but they need a minimum runway. Give them 5 years or more, and the projections converge with Nifty reality. Below 5 years, anything can happen. Beyond 5, the math begins to hold.
The simplest test. Deploy ₹5L on January 1st of any year from 2000 to 2015. Assume 12% CAGR. Then compare what the calculator promises against what Nifty actually delivered — year by year.
The chart shows two lines: the calculator's smooth exponential curve and Nifty's jagged actual path. In the first 3–4 years, they diverge wildly. Cross the 5-year mark, and the lines begin tracking each other. By 10–15 years, they converge tightly — proving the assumption was right all along, it just needed 5+ years of runway.
SIPs should converge faster than lumpsums because they average across multiple entry points. Each month you invest at a different NAV, smoothing the impact of any single bad year. The SIP Convergence Verifier tests this with month-by-month Nifty simulation.
Add annual step-up and the picture improves further. A 10% step-up SIP started in 2005 at ₹10,000/month often exceeds the calculator projection — because later, larger SIP amounts catch more of the recovery years.
Warren Buffett started investing at 11. His net worth crossed $145 billion at 94. Run the numbers: more than 97% of that wealth was built after age 52. The last decade alone — ages 84 to 94 — added roughly $75–80 billion.
This is not about Buffett's stock-picking genius. It is about the exponential nature of compounding. At 15% CAGR, ₹10L becomes ₹66L in 30 years. Hold for 50 years — just 20 more — and it becomes ₹10.8 Cr. The last 20 years do 16× the work of the first 30.
Your health, your stress levels, your sleep — these are not soft variables. They are financial variables. Every decade you extend your investing life compounds your wealth more than any alpha you could extract from market timing.
At 12% CAGR. Illustrative. The last 15 years generate 4.6× more wealth than the first 30.
"The calculator is not a prophecy — it is a destination with an uncertain route. Nifty will overshoot, undershoot, crash, and recover. The SIP will average, the step-up will tilt, and time will heal what timing cannot. But the one variable that dwarfs all others is how long you stay. Every year you remain invested is a year the math works harder than you do. Stay alive. Stay invested. Let time work."
Pick any start year (2000–2015), set your assumed CAGR, and watch calculator vs actual Nifty unfold year by year.
Open Tool →Monthly SIP with optional step-up, simulated against real Nifty returns. See when the SIP calculator meets reality.
Open Tool →Drag the sliders. Watch how the last decade dwarfs the first three. The Buffett insight, made personal.
Open Tool →