zztool What is Compound Interest?
Compound interest is the interest calculated on the initial principal and also on the accumulated interest from previous periods. In simple terms, it's "interest on interest," allowing your money to grow exponentially. Einstein once said: "Compound interest is the eighth wonder of the world. He who understands it, earns it; he who doesn't, pays it."
Compound Interest Formula
A = P(1 + r/n)ntA = Final Amount
P = Initial Principal
r = Annual Interest Rate
n = Compounding frequency per year
t = Time in years
Why Compound Interest Matters?
- ✓ Power of Time: The longer you invest, the more significant the compound effect
- ✓ Passive Income: Interest automatically reinvests without additional action
- ✓ Wealth Growth: Over time, compound interest creates exponential wealth growth
- ✓ Retirement Planning: Core concept for retirement savings and long-term investing
How to Use This Calculator?
- 1. Enter initial principal (e.g., $10,000)
- 2. Set annual interest rate (e.g., 5% for bank deposits or investment returns)
- 3. Choose investment period (recommend at least 5-10 years to see compound effects)
- 4. Select compound frequency (monthly compounding typically yields higher returns than annual)
- 5. (Optional) Set regular contribution amount and frequency (e.g., $1,000 monthly)
- 6. Click "Calculate" to view results, including charts and yearly breakdown
💡 Example
Invest $10,000 at 5% annual rate, compounded monthly, for 10 years with $1,000 monthly contributions. After 10 years, your total investment is $130,000 (principal), but the actual amount reaches approximately $155,000. The extra $25,000 is the power of compound interest!
Last Updated: 2026-06-04✓ Expert Verified
Shows growth clearly.
Great investment calculator!
Helpful for planning.