What is compound interest?

Compound interest is the interest you earn on both your original money and on the interest you've already earned. It's often described as 'interest on interest' and is a key factor in long-term wealth building.

How often is interest typically compounded?

Compounding can happen at different intervals: daily, monthly, quarterly, or annually. The more frequently interest is compounded, the faster your balance grows. This calculator assumes monthly compounding for regular contributions.

What is the 'Rule of 72'?

The Rule of 72 is a quick way to estimate how long it will take to double your money at a fixed interest rate. Just divide 72 by your annual interest rate. For example, at a 6% return, your money doubles in about 12 years.

How do monthly contributions affect compounding?

Regular monthly contributions significantly boost the effects of compounding because you are constantly increasing the principal amount that interest is calculated on. Even small, consistent additions can lead to much larger balances over several decades.

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Compound Interest Calculator - Forecast Your Savings Growth

Calculate the future value of your investments using the power of compound interest. See how monthly contributions and different compounding frequencies can accelerate your wealth growth over time.

The concept of compound interest is often called the 'eighth wonder of the world' because of its incredible ability to turn small, consistent investments into substantial wealth over time. Unlike simple interest, which is only calculated on the initial principal, compound interest is calculated on the principal plus all the interest that has accumulated in previous periods. This means your money grows at an accelerating rate, especially over long time horizons like 20, 30, or 40 years. Whether you are saving for retirement, a child's education, or a major life goal, understanding the mechanics of compounding is essential for effective financial planning.

Initial Investment

Monthly Contribution

Estimated Annual Rate (%)

Time Horizon (Years)

Currency

Investment Summary

€18,207.33

Final Balance: €18,207.33 after 10 years

Initial Investment€1,000.00

Monthly Contribution€100.00

Estimated Annual Rate (%)6%

Time Horizon (Years)10

Interest Earned€5,207.33

How it Works

This tool calculates the future value of an investment based on an initial principal, an annual interest rate, and a specific number of years. It factors in regular monthly deposits, assuming they are made at the end of each month and interest is compounded monthly. By visualizing the breakdown between your total contributions and the interest earned, you can clearly see the 'compounding effect' in action. This projection is ideal for most savings accounts, brokerage accounts, and retirement funds where interest or dividends are reinvested regularly.

Calculation Formula

FV = P(1 + r/n)^(nt) + PMT * [((1 + r/n)^(nt) - 1) / (r/n)]

Calculation Examples

1. **Long-Term Saver**: If you start with $5,000 and contribute $200 every month for 30 years at a 7% annual return, you would contribute $77,000 in total. However, thanks to compound interest, your final balance would be approximately **$274,000**.

Why use this tool in your daily life?

Compounding is the secret to true wealth. Use this tool to visualize how your future self will benefit from the small sacrifices you make today, turning 'saving' into an exciting game of long-term growth.