Compound Interest Calculator

Calculate the power of compound interest with different compounding frequencies. Compare how daily, monthly, quarterly, and annual compounding affects your returns.

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Amount added at each compounding period

The Power of Compound Interest

Albert Einstein allegedly called compound interest "the eighth wonder of the world," saying "He who understands it, earns it; he who doesn't, pays it." Compound interest is the foundation of wealth building and the key to long-term financial success.

Unlike simple interest which only earns on your principal, compound interest earns on both your principal and accumulated interest. This creates exponential growth that becomes more powerful over time.

The Compound Interest Formula

A = P(1 + r/n)^(nt)

  • • A = Final amount
  • • P = Principal (initial amount)
  • • r = Annual interest rate (decimal)
  • • n = Number of times interest is compounded per year
  • • t = Number of years

Real-World Examples

The Early Bird

Sarah invests $10,000 at age 25 and adds $200/month at 8% return. At 65, she has $700,000+. Tom starts at 35 with the same plan but only reaches $300,000.

Lesson: Starting 10 years earlier more than doubles the result!

The Debt Trap

A $5,000 credit card balance at 20% APR (compounded daily) with only minimum payments takes 15+ years to pay off and costs $8,000+ in interest.

Lesson: Compound interest works against you with debt!

The Penny Doubler

Would you rather have $1 million today or a penny that doubles every day for 30 days? The penny becomes $5.4 million on day 30!

Lesson: Exponential growth beats linear growth over time!

The 1% Difference

$100,000 invested for 30 years at 7% grows to $761,000. At 8% it becomes $1,006,000. A 1% difference equals $245,000 more!

Lesson: Small rate differences matter enormously long-term!

How to Maximize Compound Interest

1. Start as Early as Possible

Time is the most powerful factor in compound interest. Every year you delay significantly reduces your final amount.

2. Invest Consistently

Regular contributions amplify compound growth. Automate monthly investments to build wealth systematically.

3. Maximize Your Rate

Higher returns create exponentially more wealth. Compare savings accounts and investments to get the best rates available.

4. Choose Frequent Compounding

Daily compounding beats annual compounding. Most high-yield savings accounts compound daily.

5. Never Withdraw Early

Withdrawals interrupt compounding and cost you exponential future growth. Keep your money invested.

6. Reinvest All Returns

Dividends and interest should be automatically reinvested to maximize compound growth.

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