Future Value
$294,510
$130,000
Total Contributed
$164,510
Interest Earned
56%
Interest / Total
See how your money grows exponentially over time. Adjust your initial investment, monthly contributions, interest rate, and compounding frequency.
| Year | Starting Balance | Annual Contribution | Interest Earned | Ending Balance |
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Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Albert Einstein reportedly called it "the eighth wonder of the world," saying "He who understands it, earns it; he who doesn't, pays it." Unlike simple interest, which only earns interest on your original deposit, compound interest creates a snowball effect where your money grows exponentially over time.
The compound interest formula is: A = P(1 + r/n)^(nt) where A is the future value, P is the principal (initial investment), r is the annual interest rate, n is the number of times interest compounds per year, and t is the number of years. Our calculator also accounts for regular monthly contributions, which significantly accelerate wealth building.
Consider two investors. Investor A starts investing $300/month at age 25 with an 8% annual return. Investor B starts the same contribution at age 35. By age 65, Investor A has approximately $1,054,000 while Investor B has only $447,000 — a difference of over $600,000, all because of those extra 10 years of compounding. This is why financial advisors emphasize the importance of starting early.