See how money can grow when interest earns interest. Enter a starting amount, a monthly contribution and a rate. Results update as you type.
This calculator is by Stepwell Financial, which offers money education and free tools. It is the same calculator as the one on our standalone calculator page, with the same numbers. It explains how each result is worked out, so you can check every figure yourself. Stepwell Financial gives education and tools, not personal advice.
Compound vs simple interest
Compound interest
Simple interest
Total deposits
With compound interest
$31,998.32
With simple interest
$29,975.00
Compounding adds
$2,023.32
You put in $22,000.00. With compound interest, $9,998.32 of the final balance is interest.
For education only, not financial advice. The 5% starting rate is only an example, so choose your own. Real returns vary and are not guaranteed. Taxes, fees and inflation are not included.
It uses a common convention for savings accounts. Inside each compounding period your money earns simple interest month by month, and at the end of the period that interest is added to your balance and starts earning interest of its own. Your bank may work interest out differently, for example daily on your balance, so its figures can differ slightly from these. With daily compounding it uses the exact daily growth for each month. Contributions at the start of a month earn interest that month; contributions at the end start earning the next month. Every year's figure is worked out directly from the formula, so no rounding builds up. Everything runs in your browser, and nothing you type is sent to us or stored. If you use Copy link, your numbers are written into that link, so anyone you share it with can see them.