Compounding

Compounding is what happens when investment returns start generating their own returns, not just returns on your original principal. Each period's growth gets added to the base, so the next period's growth is calculated on a larger amount than before, and the effect accelerates over time.

This is the mechanism behind the well-known idea that time in the market matters more than timing the market. A modest compound interest rate sustained for decades can outperform a much higher rate sustained for only a few years, simply because compounding needs time to build momentum.

Future Value = Principal × (1 + r/n)^(n × t)

Where r is the annual rate, n is the number of times compounding occurs per year, and t is the number of years.

₹1,00,000 invested at 10% annual return, compounded annually, over 20 years:

• Future Value = ₹1,00,000 × (1 + 0.10)^20 ≈ ₹6,72,750

Compare that to simple interest at the same 10% rate over 20 years, which would only reach ₹3,00,000, less than half. The gap widens further the longer the money stays invested.

• Growth is back-loaded, not linear. Most of the total gain in a long-term compounding investment happens in the last several years, not spread evenly across the timeline.
• Compounding frequency matters less than duration. Switching from annual to monthly compounding helps, but starting a few years earlier typically helps far more.
• It works against you on unpaid debt. Credit card interest compounds the same way investment returns do, growing your balance faster the longer it's carried.
• Interruptions reset momentum. Withdrawing and reinvesting breaks the continuous compounding chain, costing more than the withdrawn amount alone over a long horizon.
• Even small rate differences matter over decades. A 2 percentage point difference in annual return can result in a dramatically different outcome over 20-30 years, not just a proportionally small gap.