Compound Interest Calculator
Model how your investments grow over time with the power of compound interest. Adjust contributions, rate, and frequency to see your potential returns.
Investment Details
Starting amount
How much you add each month
Expected yearly return (e.g., 7%)
Number of years
For inflation-adjusted results
Future Value
$691,150
After 30 years at 7% return
Total Contributions
$190,000
Initial $10,000 + $500/month
Interest Earned
$501,150
264% return on contributions
Inflation-Adjusted Value
$284,745
In today's dollars at 3% inflation
Growth Over Time
Portfolio balance and total contributions by year
Year-by-Year Breakdown
| Year | Contributions | Interest | Balance |
|---|---|---|---|
| 0 | $0 | $0 | $10,000 |
| 1 | $6,000 | $955 | $16,955 |
| 2 | $6,000 | $2,413 | $24,413 |
| 3 | $6,000 | $4,411 | $32,411 |
| 4 | $6,000 | $6,986 | $40,986 |
| 5 | $6,000 | $10,182 | $50,182 |
| 6 | $6,000 | $14,042 | $60,042 |
| 7 | $6,000 | $18,614 | $70,614 |
| 8 | $6,000 | $23,952 | $81,952 |
| 9 | $6,000 | $30,108 | $94,108 |
How These Calculations Work
Future Value with Compound Interest
FV = P(1 + r/n)^(nt) + C[((1 + r/n)^(nt) - 1) / (r/n)]
Where P = initial principal, C = periodic contribution, r = annual rate, n = compounding periods per year, t = years. The first term grows your initial investment; the second term grows your regular contributions.
Inflation-Adjusted Value
Real Value = Future Value / (1 + inflation)^years
Discounts your future balance back to today's dollars using the inflation rate, so you can understand the real purchasing power of your savings.
Frequently Asked Questions
Important Disclaimer
This calculator is for educational and informational purposes only. It does not provide financial, investment, tax, or legal advice. Results are estimates based on the assumptions you enter and may differ from actual outcomes. Past performance does not guarantee future results. Consult a qualified financial professional before making investment decisions.