What is Interest? Types and Examples Explained

Personal Finance

Have you ever wondered what “interest” is? And what are the different types of interests? In this blog post, we’ll explain how interest works, the different types of interest, and give some examples of each. 

So whether you’re a seasoned pro or a complete novice when it comes to interest rates, read on for enlightenment!

What is Interest?

Interest is the charge paid for the use of money. It is typically expressed as a percentage of the sum borrowed. It is also the price paid for borrowing money, usually over some time. When you take out a loan, you agree to pay back the principal plus interest. The amount of interest you pay depends on the terms of your loan agreement and the type of loan you have. 

For example, if you have a fixed-rate mortgage, your interest rate will remain constant throughout the life of your loan. With an adjustable-rate mortgage, your interest rate may change periodically. These depend on market conditions. In either case, interest is an important factor to consider when taking out a loan.

In addition to loans, interest can also refer to the return on investment (ROI) earned on an account or security. When you invest money in a savings account or mutual fund, you earn interest on your investment. The amount of interest earned depends on the type of investment and the current market conditions. 

For example, if you invest in a high-yield savings account, you will earn more interest than if you invest in a low-yield account. Similarly, if you invest in a bond that pays a higher interest rate than other bonds, you will earn more money from your investment. So, when choosing an investment, it is important to think about both the current interest rate and the expected return in the future.

Types of Interest

Whether you’re taking out a loan or investing your savings, understanding how simple and compound interest work can help you make choices that are in your best interests.

Nevertheless, it’s important to know how different types of interest are calculated. This will enable you to make informed decisions about borrowing and lending money. 

Simple Interest

Simple interest is a quick and easy way to calculate the interest charged on a loan. It is simply the amount of money borrowed, multiplied by the interest rate, and divided by the number of days in the loan period. 

Simple interest is easy to calculate. But it does not take into account the time value of money. This means that the borrower pays less interest overall than they would if they were charged compound interest. 

However, simple interest can be a useful way to compare different loans. When considering a loan, it is important to look at the total cost of the loan. This includes both the principal and the interest charges. By understanding simple interest, you can make informed choices about borrowing money.

All in all, with simple interest, the interest charged is a percentage of the principal amount borrowed (the amount of money you lend). 

Example of Simple Interest

When it comes to deciphering your finances, there are a lot of different formulas and terms to know. However, one of the most basic concepts is simple interest. Essentially, simple interest is calculated by taking the principal, or initial amount, and multiplying it by the interest rate and the number of periods. 

                                                       S.I = PRT

In this formula, 

P equals the principal investment amount.

R equals the annual rate of interest.

T equals the number of years the money is invested for.

So, if you had a loan with a principal of ₹10,000 and an interest rate of 5% for two years, your simple interest would be 10,0005/1002 = ₹1000. 

Of course, lenders typically compound interest. This means that they add interest payments to the principal balance. So it’s important to know how that affects your overall repayment amount. Nevertheless, understanding simple interest is a helpful first step in managing your money.

Compound Interest

Compound interest is the interest that accrues on an initial principal sum and any accumulated interest from previous periods. 

The effect of compounding depends on the frequency of compounding, or how often interest is added to the principal. The more frequently compounding occurs, the greater the effects of compounding will be. 

Compound interest can have a significant impact on long-term growth. This is why it’s important to understand how it works.

Example of Compound Interest

At its simplest, compound interest is calculated by multiplying the principal amount by one plus the annual interest rate raised to the nth power of time in years. 

The formula looks like this: 

                                             CI = P(1+ r/100)^n-P

In this formula, 

A equals the final accumulated value of the investment 

P equals the principal investment amount 

r equals the annual rate of interest 

n equals the number of times per year that interest is compounded

t equals the number of years the money is invested for

For example, let’s say you invest ₹10,000 at a 5% annual rate of return with annual compounding. After 2 years, your compound interest would be ₹1,025. If you left that same investment untouched for 20 years, CI would be worth ₹16,532.97. 

As you can see, compound interest can have a significant impact on long-term growth. That’s why it’s important to understand how it works and factor it into your investment plans.


At the end of the day, loan interest is a way for lenders to make money. So borrowers need to be aware of what they’re getting themselves into. By understanding how interest rates work and being mindful of associated fees, you can take out a loan with confidence and avoid any surprises down the line. 

We hope that now you are all clear about interest rates and their different types. But if you still need help with any of your financial doubts and concerns related to interest rates, you can contact finance experts at Piramal Finance!