Estimate how an initial investment and regular contributions could grow over time when interest is compounded. Compare the money you contribute with the interest generated by the assumed annual rate.
Enter your starting investment, regular contribution, interest rate, compounding frequency and investment period.
This summary separates the money you put into the investment from the projected growth generated by the assumed interest rate.
The chart compares your accumulated contributions with the projected account value over the investment period.
Review the projected account value at the end of each year. Contributions and interest are shown separately to make the calculation easier to understand.
| Year | Contributions | Interest | Account Value |
|---|
Suppose you start with ₦100,000, add ₦20,000 every month, earn an assumed annual rate of 15%, and compound monthly for 10 years.
The calculator does not simply multiply the interest rate by the number of years. Instead, it repeatedly applies the assumed periodic rate to the growing balance. Each new contribution then becomes part of the balance and can participate in future growth.
This calculator is a mathematical projection. It assumes that the entered annual rate remains unchanged throughout the selected period.
Compound interest is interest calculated on an amount that includes both the original principal and previously earned interest. As the balance grows, future interest can be calculated on the larger balance.
This is different from simple interest, where interest is calculated only on the original principal. Over longer periods, the difference can become significant because previously earned interest remains invested.
Compound growth becomes more noticeable over longer periods because the balance has more opportunities to generate additional growth. Starting earlier can therefore be important when building a long-term savings or investment plan.
Regular contributions increase the amount of money participating in the calculation. Earlier contributions generally have more time to grow than contributions made near the end of the investment period.
| Feature | Simple Interest | Compound Interest |
|---|---|---|
| Interest basis | Original principal | Growing balance |
| Previous interest | Usually not added to the interest base | Can become part of the balance |
| Effect of time | More linear | Can accelerate as the balance grows |
| Regular contributions | Depend on the product or calculation | Each contribution can participate in future growth |
The formula contains several important variables:
When regular contributions are involved, the calculation becomes more detailed because each contribution enters the account at a different point in time. This calculator therefore calculates the balance period by period rather than simply applying the basic formula to one principal amount.
A larger initial investment gives the calculation a larger starting balance.
Increasing regular contributions increases the amount being invested over time.
A higher assumed rate produces a higher mathematical projection, although actual returns are not guaranteed.
More time gives the balance more opportunities to compound.
With the same nominal annual rate and other assumptions, more frequent compounding can change the mathematical result.
Contributions made earlier generally have more time to participate in future growth.
A compound interest calculator can be useful when exploring hypothetical savings and investment scenarios.
The calculations on this page are performed in your browser. Your investment figures do not need to be uploaded to a server for the calculator to produce its mathematical projection.
Even though the calculator does not require financial account information, you should avoid entering confidential banking credentials, account numbers, passwords or other sensitive information into a general calculator.
This tool is intended for educational and planning purposes. A mathematical projection cannot predict the actual performance of a financial product.
Compound interest is growth calculated on a balance that can include previously earned interest. As the balance increases, future growth can be calculated on the larger amount.
No. Simple interest generally uses the original principal as the interest base, while compound interest allows previously accumulated interest to become part of the balance used for future calculations.
Over longer periods, the balance has more opportunities to generate additional growth. Regular contributions can also increase the amount participating in future compounding.
Yes. Regular contributions increase the amount invested. Earlier contributions generally have more time to participate in future growth than later contributions.
Contribution frequency describes how often you add money to the investment. Compounding frequency describes how often the assumed interest is applied to the balance. They can be different.
No. The final amount is a mathematical projection based on the assumptions you enter. Actual returns can differ because rates, fees, taxes and investment performance may change.
No. The displayed figures are nominal projected values. Inflation can reduce the purchasing power of the final amount over time.
Yes. Enter zero when you want to calculate the growth of the initial investment without additional contributions.
You can use it to explore hypothetical scenarios, but it should not be treated as financial advice or a guarantee of future investment performance.
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