Compound Interest Calculator
Calculate future value, total contributions and compound growth based on initial capital, monthly savings, years and annual return.
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Estimate how wealth can grow over time from an initial investment, a monthly contribution, an assumed annual return and an optional yearly increase of the savings rate. The comparison is most useful for long-term wealth building, ETF savings plans, retirement planning, children’s savings and fixed-income scenarios.
FAQ about Compound Interest Calculator
What is the difference between interest and compound interest?
Regular interest is earned on the original capital. With compound interest, previously earned interest or returns also create new returns. That is what accelerates long-term growth.
Can I calculate growth without monthly contributions?
Yes. If you enter 0 as the monthly contribution, the calculator only projects the growth of the initial capital.
What return should I enter?
That depends on the investment type. Cash savings products usually have lower returns than long-term stock or ETF investing. Conservative, medium and optimistic scenarios are often the best way to plan realistically.
Why can one extra year make such a big difference?
Because existing gains continue to generate additional gains in every extra year. Near the end of long periods, growth often accelerates noticeably. That is why time is one of the strongest drivers of compounding.
Is the result guaranteed?
No. This is a simplified model based on constant assumptions. Real financial markets do not grow evenly and can also experience weak periods or losses.
Is this calculator suitable for ETF savings plans?
Yes, it is very useful for rough long-term planning. For more realistic projections you should also consider costs, taxes, volatility and your personal investment strategy.
What is the benefit of increasing the savings rate each year?
Even small regular increases can significantly improve the final value. When you invest more over time, more capital benefits from future compounding, which can make a large long-term difference.
Is this calculator useful for retirement planning and children’s savings?
Yes. Compound growth becomes especially relevant for very long-term goals such as retirement, education funding or multi-decade wealth building. That makes this calculator highly useful for those plans.
Why does the calculator also show the share of contributions and growth?
This makes it easier to see how much of the final value comes from your own money and how much comes from return and compounding. Over long periods, the growth share often becomes surprisingly large.
What does the capital multiplier mean?
The capital multiplier shows in simplified form how many times your initial capital has grown. It is useful for comparing different scenarios more quickly.