Compound Interest
Compound interest is interest calculated on both the original amount of money and the previously earned interest.
It allows money to grow faster over time because interest is added repeatedly to the balance.
Why compound interest is important
Compound interest is one of the most powerful concepts in finance.
It helps:
- Grow savings faster
- Increase investment returns
- Build long-term wealth
Over long periods, even small interest rates can create significant growth.
How compound interest works
The process usually follows these steps:
- Money earns interest
- The interest is added to the balance
- New interest is calculated on the larger amount
- The cycle repeats over time
This creates exponential growth.
Simple example
If you invest €100 with 10% yearly compound interest:
- Year 1 → €110
- Year 2 → €121
- Year 3 → €133.10
Each year, interest is earned on a larger amount.
Compound interest vs Simple interest
Simple Interest
Interest is calculated only on the original amount.
Compound Interest
Interest is calculated on:
- The original amount
- Previously earned interest
This usually produces much faster growth.
Where compound interest is used
- Savings accounts
- Investments
- Retirement funds
- Loans and debt
It can help investments grow, but it can also increase debt over time.
The power of time
Time is one of the most important factors in compound interest.
The longer money stays invested:
- The more growth can accelerate
- The larger the final amount becomes
This is why long-term investing is often emphasized.
Why compound interest matters in investing
Many investors use compound growth to:
- Build wealth gradually
- Reinvest profits
- Increase long-term returns
Albert Einstein is often associated with calling compound interest “the eighth wonder of the world.”
Why learning compound interest matters
Understanding compound interest helps you:
- Understand long-term investing
- Grow savings more effectively
- Avoid expensive debt growth
- Make smarter financial decisions
It is a core concept in personal finance and investing.
A simple example
Think of compound interest like a snowball rolling downhill.
As it grows larger, it collects even more snow and grows faster.
Related terms
- What is Interest Rate?
- What is Investment?
- What is Passive Income?
Source
Information simplified from the Wikipedia article “Compound Interest”.