Compound Interest Calculator
See how savings grow with compounding and monthly contributions.
Final balance
$47,526.55
- Total contributions
- $34,000.00
- Interest earned
- $13,526.55
Year by year
| Year | Contributions | Interest | Balance |
|---|---|---|---|
| 1 | $12,400.00 | $567.39 | $12,967.39 |
| 2 | $14,800.00 | $1,286.60 | $16,086.60 |
| 3 | $17,200.00 | $2,165.39 | $19,365.39 |
| 4 | $19,600.00 | $3,211.93 | $22,811.93 |
| 5 | $22,000.00 | $4,434.80 | $26,434.80 |
| 6 | $24,400.00 | $5,843.03 | $30,243.03 |
| 7 | $26,800.00 | $7,446.09 | $34,246.09 |
| 8 | $29,200.00 | $9,253.96 | $38,453.96 |
| 9 | $31,600.00 | $11,277.11 | $42,877.11 |
| 10 | $34,000.00 | $13,526.55 | $47,526.55 |
How to use the Compound Interest Calculator
- Enter your starting amount and the expected annual interest rate.
- Set the number of years and how often interest compounds.
- Add a monthly contribution if you plan to keep saving.
- Read the final balance, total contributions and interest earned, then check the year-by-year table.
About the Compound Interest Calculator
Compound interest means you earn interest on your interest, which is why savings and investments can grow faster over time. This calculator shows the final balance of a starting amount with optional monthly contributions, how much you paid in, how much interest you earned, and a year-by-year table of the growth.
Without deposits, the balance follows A = P × (1 + r/n)^(n×t), where P is the starting amount, r is the annual rate, n is the number of compounding periods per year and t is the number of years.
To include monthly contributions for any compounding frequency, the calculator converts the rate to an effective monthly rate, (1 + r/n)^(n/12) − 1, and then moves month by month: the balance is multiplied by one plus that rate, and the contribution is added at the end of the month. Interest earned is the final balance minus your starting amount and all deposits. Results ignore taxes, fees and inflation, and real returns vary.
Frequently asked questions
What is the difference between simple and compound interest?
Simple interest is paid only on the original amount. Compound interest is paid on the original amount plus the interest already earned, so growth accelerates.
Does compounding more often help?
Slightly. Monthly compounding earns a little more than annual compounding at the same rate, and daily is a little more again, but the rate and time matter much more.
When are contributions added?
At the end of each month, after that month's interest has been applied.
Can I use this for investments?
You can model a steady expected return, but investment returns are not guaranteed and change from year to year. Use the result as an illustration, not a forecast.
Are taxes and inflation included?
No. Taxes, account fees and inflation would reduce your real growth, so your actual result may be lower.