Investment calculator with compound interest function

The result of the investment: 0
Own funds from it: 0
Interest on it: 0
Tax 15%: 0
Fees: 0

History of calculations

Investment Calculator: How Does It Work?

An investment calculator is a tool that allows individuals and investors to visualize the potential of their investments and understand how compound interest can contribute to the growth of their capital. These online calculators are invaluable for anyone looking to invest to increase their capital or save for retirement.

Understanding Compound Interest

Compound interest is often referred to as the “eighth wonder of the world” due to its ability to exponentially increase the value of an investment. In simple terms, compound interest means that the returns from your investments are reinvested, leading to growth on the interest. In other words, your money earns you more money.

Tip: Also try our mortgage calculator or percentage calculator.

Using an Investment Calculator

When using our investment calculator with the compound interest function, you need to enter several key pieces of information:

  • Initial Investment: The amount you want to invest initially.
  • Investment Duration: The number of years you plan to invest.
  • Interest Rate: This parameter represents the expected annual return on your investment, which can be based on historical data or forecasts. On January 16, 2024, for instance, investment company Portu reported a 10.5% return from their equity portfolio, while Investown on their website reported a long-term return of 9.99%.
  • Regular Contributions: Any regular deposits you plan to add to your initial investment.
  • Contribution Frequency: Our investment calculator allows for monthly, weekly, bi-weekly, and yearly regular deposit frequencies. Try different frequencies, and you might be surprised at what it can do to the final sum.
  • Annual Fee: If you plan to invest your finances in institutions like Portu or Fondee, you will certainly be paying annual fees. The calculator can model how much you’ll pay in fees over your entire investment period. It’s worth noting that similar institutions need to make a living somehow, and others, like eToro, also have their fees, which may not be as apparent (e.g., in the form of spreads on individual trades, etc.).
  • Tax: In our investment calculator, you can choose whether to calculate a 15% income tax at the end of the investment period. This will give you a clear view of the tax you will need to pay if your investment is not tax-exempt. For example, under a Long-term Investment Product (DIP), you do not have to pay tax at the end of the investment period (in retirement age). However, if you invest on platforms like the crowdfunding company Investown, you will have to pay income tax. We always recommend resolving this with an accountant or tax advisor.

How the Investment Calculator Helps You

  1. Investment Planning: Provides a clear picture of how your investments can grow over time, enabling better financial goal planning.
  2. Understanding the Impact of Compound Interest: Visualizes the significance of compound interest and its impact on your investments.
  3. Experimenting with Different Scenarios: You can play around with different amounts, investment durations, interest rates, and regular deposit frequencies to get a sense of various outcomes.
  4. Educating About Investing: Helps understand basic investment principles and how small changes can have a significant impact in the long term.

The Importance of Realistic Expectations

When using an investment calculator, it’s important to remember that the results are only estimates based on the information provided. The actual rate of return can be influenced by numerous factors, including market conditions, economic events, changes in investment strategy, or even errors in our calculator’s calculations. Please take all calculations as indicative.


The information provided by investment calculators is intended for informational purposes only and should not be considered financial advice. The results obtained from these calculators are based on user-entered data and assumptions, which may or may not reflect actual market developments or individual financial situations.

It’s important to remember that historical data is not a guarantee of future returns and that investments can lose or gain value. Prior to any investment decisions, it is advisable to consult with a qualified financial advisor to ensure that your investment strategy aligns with your personal goals, needs, and risk tolerance.

Investment calculators can be a useful tool for planning and simulating various investment scenarios, but results should always be taken with consideration of potential risks and uncertainties associated with investing.