Cumulative Interest – Know its Meaning, Formula And Example

Read on to learn more about cumulative interest rate, what is its meaning and how it is calculated in personal loans.
Personal loan
5 min read
11 December 2023

Cumulative interest is a fundamental concept in finance that represents the total amount of interest accrued overtime on a loan or an investment. Understanding cumulative interest is crucial for borrowers, investors, and anyone involved in financial transactions, as it provides insights into the long-term costs or gains associated with the use of money.

What is cumulative interest?

Cumulative interest is the sum of all interest received on investments over a certain tenure or payments made on a loan. In investments, cumulative interest results from the compounding of interest on the principal, contributing to overall growth. In the context of loans, it reflects the overall amount paid in interest on the borrowed sum. For instance, with a personal loan, personal loan interest rates accumulate as a percentage of repayments that are made on the principal. Understanding cumulative interest is essential for borrowers to grasp the full cost of loans, emphasizing the impact of time on financial outcomes.

How is cumulative interest calculated on a personal loan?

The calculation of cumulative interest on a personal loan depends on the method used by the lender. Two common methods are the reducing balance method and the flat interest rate method. The reducing balance method is more common and usually results in lower cumulative interest over time, as the interest is calculated on the remaining balance. In contrast, the flat interest rate method charges interest on the entire principal throughout the loan tenure.

When considering a personal loan, it's crucial to inquire about the specific method used by the lender to understand how interest accrues and how it impacts the overall cost of the loan. Always review the loan agreement and terms to ensure clarity on the calculation method and any associated fees.

Example of cumulative interest on personal loan

Assessing cumulative interest is a valuable method to understand the total cost of your loan. However, it's important to note that this calculation doesn't consider potential charges imposed by your lender, such as processing fees or prepayment penalties.

Here is an example of cumulative interest on a personal loan using the flat interest rate method. Suppose you take a personal loan of Rs. 50,000 with a flat interest rate of 12% per annum, and the loan tenure is three years.

The formula for calculating the total interest is Total Interest=P×r×t

where:

  • P is the principal loan amount = Rs. 50,000
  • r is the flat annual interest rate = 0.12
  • t is the number of years = 3

Total Interest = 50,000×0.12×3

By calculating this, you find the total interest would be Rs. 18,000. This means, that in addition to repaying the Rs. 50,000 principal amount, you would have to pay Rs. 18,000 in interest, resulting in a total repayment of Rs. 68,000 over the three years. You can also utilise our EMI calculator, which breaks down individual interest payments, aiding in the determination of the overall sum.

Cumulative interest vs. Compound interest

Understanding the differences between these two types of interest is crucial for financial literacy and informed decision-making.

Cumulative Interest:

  • Total interest accrued on the original principal.
  • Calculated using simple interest.
  • Does not consider interest compounding over time.
  • Common in basic interest calculations.
  • Amount paid remains constant throughout the period.

Compound Interest:

  • Interest calculated on the initial principal and accumulated interest.
  • Involves regular compounding periods.
  • Total amount subject to interest increases over time.
  • Common in loans, investments, and savings accounts.
  • Typically compound interest results in higher overall interest payments. To calculate compound interest using a compound interest calculator, input the principal amount, interest rate, compounding frequency, and the time period.
  • Reflects the effect of compounding on the total owed or earned.

In summary, when you are borrowing a loan, cumulative interest is a fundamental concept that directly influences the financial outcomes of the transactions. Being aware of how it works empowers you to make informed decisions about your loans, ultimately contributing to better financial management and planning.

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Frequently asked questions

What is the meaning of cumulative interest?

Cumulative interest refers to the total amount of interest that accrues on the original principal amount over a specific period. It is calculated using the simple interest formula, where the interest is applied solely to the initial amount borrowed or invested without considering compounding effects.

How do you calculate cumulative interest?

To calculate cumulative interest, use the formula: Cumulative Interest = Principal × Rate × Time. Multiply the principal amount by the interest rate and the time the money is borrowed or invested. This formula applies simple interest, assuming a linear progression of interest over time without compounding effects.

What is the difference between interest and cumulative interest?

Interest is the cost of borrowing money or the return on investment, calculated on the principal amount. Cumulative interest, on the other hand, is the total amount of interest accrued on the original principal over time, typically calculated using the simple interest formula without considering compounding effects.

Is cumulative interest good?

Cumulative interest can be positive or negative based on context. In savings, it represents earnings, which is beneficial. In loans, it signifies the total cost paid by the borrower, which may be considered unfavourable. The assessment depends on whether one is earning or paying the cumulative interest.

Who benefits from compound interest?

Investors benefit from compound interest. When funds are reinvested or savings grow over time, compound interest leads to accelerated growth. It allows for the compounding of returns on investments or savings, resulting in larger overall returns compared to simple interest over extended periods.

How can I calculate compound interest?

To calculate compound interest using a compound interest calculator, input the principal amount, interest rate, compounding frequency, and the time period. The calculator then applies the compound interest formula and provides accurate results.

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