Compound Interest
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods, causing your money to grow exponentially over time.
Detailed Explanation
## What Is Compound Interest? Compound interest is often called the eighth wonder of the world, and for good reason. Unlike simple interest (which is calculated only on the original principal), compound interest is calculated on the principal plus all previously earned interest. This creates a snowball effect where your money grows faster and faster over time. ## The Formula A = P x (1 + r)^n Where: - A = Final amount - P = Principal (initial investment) - r = Interest rate per compounding period - n = Number of compounding periods ## How It Works in PPF PPF compounds annually at 7.1%. Here's what that means for Rs 1,00,000: - After 1 year: Rs 1,07,100 - After 5 years: Rs 1,40,826 - After 10 years: Rs 1,98,315 - After 15 years: Rs 2,79,019 Your money nearly triples in 15 years without you adding a single rupee. When you add Rs 1,50,000 every year, the compounding effect is even more dramatic because each new deposit starts its own compounding journey. ## Why Compounding Frequency Matters PPF compounds annually (once per year). Some instruments compound quarterly or monthly, which produces slightly higher returns at the same nominal rate. For example, 7.1% compounded quarterly gives a slightly higher effective rate than 7.1% compounded annually. However, PPF's annual compounding at 7.1% tax-free still beats most alternatives. Explore the math with our [Compound Interest Calculator](https://compound-calc-8c8.pages.dev) or see PPF-specific projections with our [PPF calculator](/).