Compound Interest Calculator
Calculate how your initial principal grows over time using the compound interest formula.
Results
Future Value
$20,096.61
Total Interest Earned
$10,096.61
Total Contributions
$10,000.00
Year-by-Year Growth
| Year | Balance | Interest | Growth |
|---|---|---|---|
| 1 | $10,722.90 | $722.90 | $722.90 |
| 2 | $11,498.06 | $775.16 | $1,498.06 |
| 3 | $12,329.26 | $831.20 | $2,329.26 |
| 4 | $13,220.54 | $891.28 | $3,220.54 |
| 5 | $14,176.25 | $955.71 | $4,176.25 |
| 6 | $15,201.06 | $1,024.80 | $5,201.06 |
| 7 | $16,299.94 | $1,098.89 | $6,299.94 |
| 8 | $17,478.26 | $1,178.32 | $7,478.26 |
| 9 | $18,741.77 | $1,263.51 | $8,741.77 |
| 10 | $20,096.61 | $1,354.84 | $10,096.61 |
How Compound Interest Works
This calculator applies the compound interest formula A = P(1 + r/n)^(nt), where P is principal, r is annual rate, n is compounding periods per year, and t is years. It shows your projected balance for each year and how much growth comes from interest.
Understanding the Compound Interest Formula
Compound interest means your money earns interest on both the original principal and previously earned interest. Increasing either the rate, the compounding frequency, or the time horizon raises your future value. Over long periods, time is usually the most powerful factor.
Frequently Asked Questions
The Rule of 72 estimates how long it takes to double your money by dividing 72 by your annual return. At 8%, doubling takes about 9 years (72 ÷ 8). It is a quick estimate and works best between roughly 4% and 12% rates.