Finance
Compound Interest Calculator
See how your money grows over time with compound interest. Adjust the numbers and watch the chart update instantly.
Final balance
$302,370
Total contributed
$130,000
Interest earned
$172,370
Year-by-year breakdown
| Year | Balance | Contributions | Interest |
|---|---|---|---|
| 0 | $10,000 | $10,000 | $0 |
| 2 | $24,413 | $22,000 | $2,413 |
| 4 | $40,986 | $34,000 | $6,986 |
| 6 | $60,042 | $46,000 | $14,042 |
| 8 | $81,952 | $58,000 | $23,952 |
| 10 | $107,144 | $70,000 | $37,144 |
| 12 | $136,110 | $82,000 | $54,110 |
| 14 | $169,416 | $94,000 | $75,416 |
| 16 | $207,710 | $106,000 | $101,710 |
| 18 | $251,742 | $118,000 | $133,742 |
| 20 | $302,370 | $130,000 | $172,370 |
Frequently asked questions
What is compound interest?
Compound interest is interest earned on both your original money AND on the interest you've already earned. It's interest on interest — which is why it grows faster over time. The more frequently it compounds (monthly vs annually), the faster it grows.
How is this calculated?
We use the formula A = P(1 + r/n)^(nt) + monthly contributions compounded at the same rate. P is your starting amount, r is the annual rate, n is how many times per year it compounds, and t is the number of years.
Does this account for taxes or inflation?
No. This calculator shows gross growth before taxes and doesn't adjust for inflation. Real-world returns will be lower after these factors. Use this as a planning tool, not financial advice.
What's a good rate of return to use?
The S&P 500 has historically returned about 7-10% annually before inflation. A conservative estimate is 5-7%. For high-yield savings, use 3-5%. Adjust based on your investment type and risk tolerance.
Use our free compound interest calculator to see how your investments grow over time. Enter your initial deposit, monthly contribution, expected annual return, and investment period to visualize growth with an interactive chart.
Perfect for retirement planning, savings goal tracking, and comparing investment strategies. Adjust any variable and watch the projection update in real time — no signup required.