FINANCIAL CALCULATOR
Compound Interest
See how regular contributions and compound growth could add up over time. Change the assumptions to compare outcomes.
← Back to all toolsGrowth assumptions
Set a starting balance, regular savings and an estimated return.
PROJECTED VALUE
Contributions are added at the end of each month; interest is compounded monthly.
Projected growth
Projected balance over the selected period.
Year-by-year growth
Illustrative projections, not guaranteed returns.
| Year | Contributions | Interest earned | Balance |
|---|
Estimates only, not financial advice. This illustration assumes a constant annual return and monthly deposits at month-end. Actual returns, fees, taxes and inflation can change results.
GROWTH PLANNING GUIDE
See how compounding and regular deposits interact
Compound interest means that growth can be earned on both the starting balance and earlier growth. Adding money regularly can increase the amount exposed to future growth, although real investment returns are not guaranteed and can be negative. This calculator is best used to compare assumptions and understand the mechanics, not to predict market performance.
How to use the Compound Interest Calculator
- Enter the starting balance and the amount you plan to contribute each month.
- Choose an annual interest-rate assumption and the number of years to model.
- Select a compounding frequency and currency, then calculate the projection.
- Review the ending balance, total contributions and estimated interest separately. Try a lower rate to understand how sensitive the result is.
Tips and common mistakes
Do not treat an assumed return as a promise. The result does not automatically account for investment fees, taxes, inflation, missed deposits or changing rates. Check whether your contribution timing matches the assumption displayed under the result. Small changes in the annual rate or duration can create large differences over long periods, so compare several reasonable scenarios rather than focusing on one number. For savings products, use the rate and deposit rules provided by the institution.
How the calculation works
With periodic compounding and no extra deposits, the familiar formula is future value = principal × (1 + rate ÷ periods)periods × years. Regular deposits add another series of contributions, each of which has its own time to grow. For a simple example, 10,000 invested for one year at 12% annual interest compounded monthly, with no deposits, grows to about 11,268 before fees and taxes: 10,000 × (1 + 0.12 ÷ 12)12. This tool also models monthly contributions at the end of each month; the displayed assumption explains how the chosen compounding option is represented in the estimate.
Frequently asked questions
Is the interest rate guaranteed?
No. It is an input assumption, and actual rates and returns can change.
Are monthly deposits included?
Yes. Enter your planned monthly contribution; the result states the deposit-timing assumption.
Are taxes and fees included?
No. Treat the result as a before-cost illustration unless you account for those separately.
Why is compounding frequency important?
It affects how often growth is applied, though actual product terms can use different conventions.
Is this financial advice?
No. It is an educational estimate and not a promise of returns or a personal recommendation.
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