Try a savings scenario
Enter a starting amount, a chosen nominal annual rate, monthly deposits, and whole years. The result separates what you put in from estimated interest.
Starting with 1,000.00, depositing 100.00 at each month-end, and using 6% nominal annual interest for 10 years, the estimated balance is 18,207.33. Contributions total 13,000.00; estimated interest is 5,207.33.
How compounding works here
The monthly rate is the annual percentage ÷ 100 ÷ 12. For every month, the calculator multiplies the previous balance by one plus that monthly rate, then adds the deposit. It keeps full precision through the calculation and rounds displayed amounts to two decimals.
With no deposits, the equivalent formula is starting balance × (1 + annual rate ÷ 1200) raised to the number of months. With a zero rate, simply add every deposit to the starting amount.
Investor.gov’s compound-interest calculator also distinguishes starting money, recurring contributions, time, and an estimated rate. This calculator specifically uses monthly compounding and month-end deposits.
Read it as an illustration
This is not financial advice or a forecast. It assumes a constant nonnegative nominal rate from 0 to 100%, 1 to 100 whole years, and no withdrawals. Starting amounts and monthly deposits can each be zero to 10,000,000. The tool rejects results above 1 trillion. It does not connect accounts or fetch market data. Try several assumptions rather than treating one result as certain.