Compound Interest Calculator (Savings)
See how your savings could grow over time with regular deposits and compound interest. Free.
In plain words: Enter what you start with, how much you'll add each month, the interest rate and the years to see how it could grow. It's a projection, not a promise, as real rates change.
| Year | Total Contributed | Compound Interest | Ending Balance |
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How to Use Compound Interest Calculator (Savings)
- Enter your Initial Deposit, Monthly Contribution and Annual Growth Rate (%), then drag the Time Horizon slider (1 to 45 years).
- The summary cards and stacked bar chart update instantly to show your projected balance, total cash contributed and total compound interest earned.
- Check the year-by-year schedule below or download it as a CSV spreadsheet.
How Compound Growth and Regular Investing Work
Compound interest means your returns start earning returns of their own. This calculator compounds monthly and adds your contribution at the end of each month. For a starting sum P, monthly contribution PMT, annual rate r and t years, the future value FV is:
FV = P ร (1 + r/12)^(12t) + PMT ร [((1 + r/12)^(12t) โ 1) รท (r/12)]
The results do not adjust for inflation, fees or tax. To get a rough real-terms figure, try a lower growth rate (for example, subtract 2 to 3 points for inflation). Even modest monthly contributions inside a tax-efficient wrapper, such as a UK Stocks & Shares ISA (up to ยฃ20,000 a year), can see the interest earned overtake the cash paid in after a decade or two of steady growth.