<div id="ci-results" class="grid grid-cols-1 sm:grid-cols-3 gap-4 mb-6">
        <div class="bg-indigo-50 p-4 rounded-xl text-center border border-indigo-100">
            <div class="text-[10px] font-bold text-indigo-600 uppercase tracking-widest mb-1">Final Amount</div>
            <div id="ci-final" class="text-xl font-extrabold text-indigo-700 font-mono"><span class="currency-text">$</span>2,15,892</div>
        </div>
        <div class="bg-emerald-50 p-4 rounded-xl text-center border border-emerald-100">
            <div class="text-[10px] font-bold text-emerald-400 uppercase tracking-widest mb-1">Interest Earned</div>
            <div id="ci-interest" class="text-xl font-extrabold text-emerald-600 font-mono"><span class="currency-text">$</span>1,15,892</div>
        </div>
        <div class="bg-slate-50 p-4 rounded-xl text-center border border-slate-200">
            <div class="text-[10px] font-bold text-slate-500 uppercase tracking-widest mb-1">Effective Annual Rate</div>
            <div id="ci-effective" class="text-xl font-extrabold text-slate-700 font-mono">8.30%</div>
        </div>
    </div>

    <div class="bg-amber-50 p-4 rounded-xl border border-amber-200 text-center">
        <p class="text-sm text-amber-800"><strong>📏 Rule of 72:</strong> At <span id="ci-rule72-rate">8</span>% interest, your money doubles in approximately <strong id="ci-rule72-years">9</strong> years.</p>
    </div>
</div>

What is Compound Interest?

Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest (calculated only on the principal), compound interest grows exponentially over time — this is why Albert Einstein allegedly called it the "eighth wonder of the world."

Whether you're saving in a bank fixed deposit, investing in mutual funds through SIPs, or growing a retirement corpus, compound interest is the engine that multiplies your wealth.

The Compound Interest Formula

Compound Interest vs. Simple Interest

How Compounding Frequency Affects Your Returns

The more frequently interest is compounded, the more you earn. Here's a comparison for a $1,000 investment at 10% for 10 years:

The Rule of 72: A Quick Mental Math Trick

The Rule of 72 is the fastest way to estimate how long it takes to double your money. Simply divide 72 by the annual interest rate:

Compound Interest in Real-World Investments

Compound interest powers virtually every investment vehicle:

• Mutual Fund SIPs: Monthly investments compound over time. Use our SIP Calculator to see the effect of step-up compounding.
• Fixed Deposits (FDs): Banks compound quarterly. An 8% FD actually yields 8.24% effective annual return.
• PPF (Public Provident Fund): Compounds annually at government-set rates (currently 7.1% worldwide).
• Stock Market: Reinvested dividends compound over decades, which is why long-term equity investors dramatically outperform short-term traders.