Compound Interest Calculator
See how your money grows with the power of compounding over time.
A = P(1 + r/n)^(nt) CI = A − P
Compound Interest Calculator – The 8th Wonder of the World
Albert Einstein reportedly called compound interest "the eighth wonder of the world." Our compound interest calculator shows you exactly how your wealth grows exponentially when earnings are reinvested. The difference between simple and compound interest becomes dramatic over long time horizons.
The Power of Compounding
At 8% annual return, $10,000 invested for 30 years grows to:
- Simple Interest: $34,000 ($24,000 in interest)
- Annual Compounding: $100,627 (~10× your money)
- Monthly Compounding: $109,357 (~11× your money)
- Daily Compounding: $110,232 (~11× your money)
The Rule of 72
A quick mental math trick: divide 72 by your annual interest rate to estimate how many years it takes to double your investment. At 8% interest: 72 ÷ 8 = 9 years to double. At 6%: 72 ÷ 6 = 12 years. At 12%: 72 ÷ 12 = 6 years.