Compound Interest Calculator

Transform your investments and achieve financial goals with the power of compound interest. Our compound interest calculator simplifies your investment planning, allowing you to visualize the growth of your wealth and optimize your returns. Discover how small regular contributions can multiply over time, paving the way for realising your financial goals, such as retirement, children’s education, or the acquisition of assets.

Compound interest effect

Compound interest calculator: an essential tool

Our compound interest calculator is an indispensable tool for financial planning and investments. It allows you to estimate the future value of an investment considering different interest rates, time periods, and regular contributions.

Try different scenarios and see how simple adjustments can significantly impact the growth of your investment.

*Calculator results are simulations. It does not represent any kind of financial advice.

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How to use the compound interest calculator

How to use:

  • Initial investment: is the amount of money that you will invest at first.
  • Interest Rate: the rate you expect to earn on your investment. Normally annualized.
  • Additional investment: the amount you intend to add on top of the investment and the frequency of it.
  • Duration or term: is the time in years that the investment will take place.
  • Interest is compounded: the frequency with which interest is calculated on your investment.

What is the compound interest?

Compound interest is given by the accumulation of interest generated over a certain time from a capital at an interest rate during certain application periods. This means that at the end of each period, a larger amount is obtained during the new period using the same interest rate.

Characteristics of compound interest

The main characteristic of compound interest, which differentiates it from simple interest, is that this financial model allows the reinvestment of capital plus interest in each exercise period.

By capitalizing the investment, the reinvested capital in each period is greater, gradually increasing the amount of interest obtained. It’s a kind of downward snowball that allows obtaining a higher return over time using the same initial capital.

However, another characteristic of compound interest investment products is that the interest generated by the capital cannot be sold until the established term has ended.

Unlike simple interest, where you can withdraw the earnings and reinvest the same capital in compound interest, the key is precisely that the interest generated in each period increases the initial capital. If any amount of money is withdrawn, this would result in non-compliance with the compound interest formula.

Compound interest formula

The compound interest is calculated as shown in the formula below. We will only need to have some data, such as the initial capital, interest, and the period. The first step is to understand the variables of this calculation:

VA=VF (1 + i)^n

  • VF = is the initial value of the operation, that is, the amount you invested;
  • VA = the value you will receive at the end of the period, that is, initial value + interest;
  • i = interest rate, the factor used to multiply the capital.
  • n = is the period for which the rate will apply to the initial value.

Example of compound interest calculation

We give an example of how to calculate investments, and then we will explain the numbers:

John invests an initial capital of 5,000 pounds in a simple interest financial product that generates a 2% interest rate for one year. At the end of the term, John gets his initial capital plus the simple interest generated during this time, that is, 5,100 pounds.

Now, suppose that John uses these same 5,000 pounds plus the profit from this first year (100 pounds) to generate compound interest at the same rate of 2%. At the end of the period (which we estimate at 12 years), the total profit from the investment would be 6,341.21 pounds.

Invested Capital (£)
Generated Interest (2% AER)
Total (£)

As we can see, the interest rate does not change at any time; however, maintaining the same 2% and applying compound interest increases the capital in each period using the interest earned in the previous period. That is, each time the capital is greater, the interest generated will be greater, and this is added to the capital, which in turn is reinvested, resulting in a total much higher than what would be obtained with simple interest.

What is the difference between simple and compound interest?

In the simple interest regime, the percentage of interest applies only to the initial capital. This means that the remuneration on the money will only apply to the amount invested or initially borrowed.

The main differences between simple and compound interest are the following:

Simple interest

Among the characteristics of simple interest that stand out are the following:

    • The initial capital does not change, remaining the same throughout the operation.

    • The interest does not change, being the same for each period of the operation.

    • The interest rate is applied to the invested capital or the initial capital.

Compound interest

The main characteristics of compound interest are:

    • The initial capital increases each period as the interest increases.

    • The interest rate is applied to the capital, which will vary.

    • The interest will increase.

The difference between simple interest and compound interest is based on the capitalization of interest on capital. That is, simple interest does not accumulate the interest generated by the capital to reinvest it; instead, it is a linear formula with the same result in each period, as long as the interest rate and term are constant.

The main differences between simple interest and compound interest are:

    • In simple interest, the initial capital is the same throughout the entire operation, while in compound interest, this capital varies each period.

    • The interest is the same in simple interest, while the interest in compound interest varies each period.

Maximizing the power of compound interest | Investment strategies: From 1,000 to 100,000 Pounds

Regardless of the initial amount — be it 1,000, 5,000, 20,000 or 100,000 pounds —the secret to achieving significant wealth growth lies in the intelligent application of compound interest. Here is a concise guide to adjust your investment strategies according to the available capital to maximize long-term return:

    • For beginners investors: With just 1,000 pounds, explore low-cost, high-growth potential investment options such as ETFs and investment funds. An early start is key to maximizing compound interest. 

    • Stepping up the game: When investing 5,000 pounds, consider diversifying with individual stocks, thematic ETFs, and bonds, seeking a balance between risk and return. 

    • Expanding horizons: With 20,000 pounds, diversification becomes crucial. Combine asset classes like real estate and cryptocurrencies with traditional investments to minimize risks and maximize returns. 

    • Important decisions for large amounts: When managing 100,000 pounds, seeking financial advice to customize your investment strategy, focusing on high-performance funds and exclusive opportunities that enhance the benefits of compound interest is advisable.

Brokers and ISAs that make your money grow

Choosing a broker that values and remunerates the deposited capital is a significant differential in finance. Some brokers exceed the traditional offer by applying compound interest on uninvested balances, ensuring that your money remains and grows. This remuneration model demonstrates a commitment to appreciating investors’ resources and promoting more efficient and sustainable wealth growth.

Also read:

👉 Best Buy and Hold Brokers

👉Best ISA Stocks and Shares

This article is purely informative and educational. It cannot be considered financial advice or a buy/sell recommendation.


What are compound interests?


Compound interests are those added to the initial capital and on which new interests are generated. In this case, the interests generated are added period by period to the initial capital and to the interests already generated.


What is the difference between simple interest and compound interest?


In simple interest, the initial capital remains the same throughout the entire operation, while in compound interest, this capital varies each period. The interest is the same in simple interest, while in compound interest, the interest varies each period.


What are the advantages of compound interest?


Its main advantage is that all the interest generated is continuously added, which means that interest is generated, and we can increase our capital much more quickly. The profits obtained are added to the initial capital at the end of each period.


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