Et Money Compound Interest Calculator
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Reviewed by Calculator Editorial Team
Compound interest is a powerful financial concept where your earnings earn interest over time. This calculator helps you determine how much your ET Money investments will grow with compound interest.
What is Compound Interest?
Compound interest is the process where interest is added to the principal sum of a deposit or loan, and future interest calculations are based on this new amount. Unlike simple interest, which only calculates interest on the original principal, compound interest allows your money to grow exponentially over time.
This is why compound interest is often referred to as "money making money." The earlier you start investing, the more time your money has to grow through compounding.
How to Calculate Compound Interest
Calculating compound interest involves several key factors:
- Principal (P) - The initial amount of money
- Annual Interest Rate (r) - The yearly interest rate (expressed as a decimal)
- Number of Times Interest is Compounded per Year (n) - How often interest is applied (monthly, quarterly, annually)
- Time (t) - The number of years the money is invested
The calculation involves raising the principal to the power of the compounding periods and multiplying by the interest rate.
The Compound Interest Formula
Compound Interest Formula
A = P(1 + r/n)nt
Where:
- A = the future value of the investment/loan, including interest
- P = principal investment amount
- r = annual interest rate (decimal)
- n = number of times that interest is compounded per year
- t = time the money is invested for, in years
This formula shows how the principal grows over time with compound interest. The more frequently interest is compounded, the faster your money grows.
Worked Example
Let's say you invest £1,000 at an annual interest rate of 5%, compounded quarterly for 10 years.
Example Calculation
Principal (P) = £1,000
Annual Interest Rate (r) = 5% = 0.05
Compounding Frequency (n) = 4 (quarterly)
Time (t) = 10 years
Future Value (A) = £1,000(1 + 0.05/4)4×10 = £1,000(1.0125)40 ≈ £1,790.85
After 10 years, your investment would grow to approximately £1,790.85 with compound interest.
Frequently Asked Questions
How does compound interest work?
Compound interest works by adding the interest earned to the principal, so future interest calculations are based on this new amount. This creates exponential growth over time.
What is the difference between simple and compound interest?
Simple interest is calculated only on the original principal, while compound interest is calculated on the principal plus any accumulated interest from previous periods.
How often should interest be compounded?
The more frequently interest is compounded, the faster your money grows. Common compounding periods are annually, semi-annually, quarterly, and monthly.