Compound Interest Calculator
Use this compound interest calculator to see how your money grows with an initial deposit and monthly contributions. Enter your starting balance, how much you add each month (e.g. from your paycheck), the interest rate, and years—get your future value and total interest earned.
How to use this compound interest calculator
Enter your initial savings, monthly contribution (what you can set aside from each paycheck), expected annual return (e.g. 7% for long-term investing or 4–5% for high-yield savings), and number of years. The calculator compounds monthly and shows how much you’ll have and how much of that is interest.
Why use a compound interest calculator?
A compound interest calculator shows how savings grow when interest is reinvested. Adding a fixed amount from each paycheck (e.g. to a savings account or investment) can grow much more than you might expect over 10–30 years. Use it to set a monthly savings goal after you know your take-home pay from our paycheck calculator, and to compare different rates and time horizons.
When does compound interest matter most?
Compound interest has the biggest impact over long periods and when you contribute regularly. Retirement accounts, high-yield savings, and long-term investing all benefit—the earlier you start, the more time growth has to compound. Use this compound interest calculator to see how even a small monthly amount (e.g. $200 from your paycheck) can grow over 20–30 years at a reasonable rate.
Tips for growing savings with compound interest
Automate contributions so a portion of each paycheck goes to savings or investments before you spend it. Use a high-yield savings account for emergency funds (current APY often 4–5%) and invest for long-term goals so growth can compound. Run this calculator with different monthly amounts and rates to see how small increases in contribution or time can significantly raise your future value. Pair it with our savings goal and retirement calculators to plan specific targets.