Free Finance Tool
Compound Interest Calculator
Enter your principal, interest rate, and time horizon to instantly visualize how your money compounds and grows year by year.
$
%
$
Principal: $10,000.00Rate: 8%Years: 20
After 20 years, your $10,000.00 grows to $46,609.57 at 8% compounded annually.4.66x growth
$46.6KFinal Balance
$10.0KTotal Invested
$36.6KInterest Earned
4.66xGrowth Multiple
78.5%Interest Share
Growth Chart
Total BalanceTotal Invested
Year 20Balance: $46,609.57Invested: $10,000.00Interest: $36,609.57
Hover over the chart to inspect year-by-year values
Year-by-Year Breakdown
| Year | Total Balance | Total Invested | Interest Earned | Interest Share |
|---|---|---|---|---|
| 0 | $10,000.00 | $10,000.00 | $0.00 | |
| 1 | $10,800.00 | $10,000.00 | $800.00 | |
| 2 | $11,664.00 | $10,000.00 | $1,664.00 | |
| 3 | $12,597.12 | $10,000.00 | $2,597.12 | |
| 4 | $13,604.89 | $10,000.00 | $3,604.89 | |
| 5 | $14,693.28 | $10,000.00 | $4,693.28 | |
| 6 | $15,868.74 | $10,000.00 | $5,868.74 | |
| 7 | $17,138.24 | $10,000.00 | $7,138.24 | |
| 8 | $18,509.30 | $10,000.00 | $8,509.30 | |
| 9 | $19,990.05 | $10,000.00 | $9,990.05 | |
| 10 | $21,589.25 | $10,000.00 | $11,589.25 | |
| 11 | $23,316.39 | $10,000.00 | $13,316.39 | |
| 12 | $25,181.70 | $10,000.00 | $15,181.70 | |
| 13 | $27,196.24 | $10,000.00 | $17,196.24 | |
| 14 | $29,371.94 | $10,000.00 | $19,371.94 | |
| 15 | $31,721.69 | $10,000.00 | $21,721.69 | |
| 16 | $34,259.43 | $10,000.00 | $24,259.43 | |
| 17 | $37,000.18 | $10,000.00 | $27,000.18 | |
| 18 | $39,960.19 | $10,000.00 | $29,960.19 | |
| 19 | $43,157.01 | $10,000.00 | $33,157.01 | |
| 20 | $46,609.57 | $10,000.00 | $36,609.57 |
Understanding compound interest
Compound interest means you earn interest on both your principal and the interest already accumulated
The more frequently interest compounds, the faster your balance grows due to intra-period compounding
Time is the most powerful variable: doubling the number of years has a far greater effect than doubling the rate
Use the Rule of 72 as a quick check: divide 72 by your interest rate to estimate years to double your money
Regular monthly contributions dramatically accelerate growth by continuously adding to the compounding base
The gap between the invested amount and final balance represents entirely passive interest income
Starting earlier matters more than starting with a larger amount due to exponential growth over time
Hover over the chart to inspect the exact balance, invested amount, and interest earned at any specific year
Export the CSV to paste into a spreadsheet or share the year-by-year schedule with a financial planner
This calculator assumes a constant interest rate and does not account for inflation or taxes on gains
