Savings Growth
Compound Interest Calculator
See how an initial deposit plus regular contributions grow over time, at any compounding frequency.
Growth over time
View year-by-year growth table
| Year | Contributed | Interest | Balance |
|---|
How compound interest works
Compound interest means you earn returns not just on your original deposit, but on all the interest that deposit has already earned — so your balance grows faster and faster over time rather than by a fixed amount each period. This calculator applies your annual rate divided by the compounding frequency you choose (daily, monthly, quarterly, or annually) to your running balance at each period, then adds your monthly contribution on top, repeating for the number of years you specify.
Compounding frequency has a smaller effect than most people expect — daily compounding will out-earn annual compounding at the same stated rate, but the difference is usually modest compared to the effect of the interest rate itself or how long you leave the money invested. The biggest lever in this calculator is almost always time: the longer your horizon, the larger the share of your final balance that comes from growth rather than your own contributions, which is the year-by-year table below illustrates directly.
Does compounding frequency matter much?
It matters, but less than most people assume — moving from annual to daily compounding at the same rate typically adds a small amount to your final balance, far less than the effect of a higher interest rate or a longer time horizon.
Why does the "interest earned" portion grow so much in later years?
Because interest is calculated on an ever-larger balance that includes all previously earned interest — so in later years, more of your growth comes from interest-on-interest than from new contributions.