How to Calculate Loan Interest
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How to Calculate Loan Interest

January 10, 2023
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How to Calculate Loan Interest

Taking a loan always requires a careful approach, so every borrower should consider many aspects. As a rule, people want emergency money immediately when struggling with serious financial troubles.

About Loan Interest, What Is It?

Interest rates are one of the most crucial aspects of the loan, so let’s look closely at how it works and what it means. Lending companies that provide their service for all categories of borrowers impose additional charges over the initial loan amount. In short, lenders get a particular percentage of the principal in exchange for their service. For example, when you apply for $20,000, the sum you must repay may total $23 000. It means that the lender gets $3,000 for providing you the opportunity to take this money. Interest rates refer to APR (Annual Percentage Rate), which denotes the cost of funds charged on loans. To put it simply, APR defines the amount of money you pay for being able to use cash taken from financial institutions. It applies to all types of loans, such as personal loans, mortgages, payday loans, auto loans, student loans, and so on. Whether you get money for furniture purchases, grocery shopping, or tuition fees doesn’t matter. In all cases, you must meet the requirement of interest rates. Every borrower has the right to choose the most convenient repayment plan, but in the end, the repaid sum can be significantly higher than your initial loan amount.

Interest rates vary slightly in every place, but lenders set their own requirements and limitations under the control of local governmental legislation. Furthermore, charges depend on your creditworthiness. It means borrowers with bad credit scores have to pay higher interest rates than those with excellent credit scores.

Hence, borrowers should pay great attention to this percentage, which can fluctuate over time, making significant changes to the whole amount of money they should repay. Understanding the most basic points about loans will help you make the right decision and prevent you from falling into a trap.

How to Calculate Interest Rate on a Loan?

After understanding what interest rates mean, it is time to learn how to calculate them properly. Bank workers do it by themselves, though you can try to calculate it on your own to understand better how it works.

There is a common formula for all loan types:

Principal loan amount × Interest rate × Time = Interest rate

Let’s look at a simple example to make all points clear.

You apply for a three-year loan for $15,000, and the interest rate is 5%. Then you should make a simple calculation according to the formula. It will look like this:

$15,000 (principal loan amount) × 0.05 (Interest rate) × 3 (Time) = $2 250

Thus, this simple calculation shows that lenders will charge you $2,250 over the initial amount of the loan, or to put it in another way, borrowers should pay an extra $2 250 when taking only $15,000. This information will help you get familiar with the process of getting a loan and figure out how lenders define interest rates for every loan type.

What Can Impact Your Interest Over the Loan?

Interest rates vary at different lending companies, and not only local legislation defines these fluctuations. Many factors can impact your interest on the loan. Thus, before applying for a cash advance, you should examine all necessary information about its regulations to know what to expect when reaching out to financial institutions.

Credit score

Borrowers with poor credit score are obliged to pay higher interest rates as a penalty. Therefore, it is advisable to think twice before submitting the request for the loan because the default of repaying it can lead to terrible consequences. On the contrary, people with good or excellent credit score will pay lower interest rates. According to common guidelines, a credit score below 600 is considered bad. So, if you want to pay a lower interest rate, take all the necessary measures to improve it.

Credit history

If it is almost blank, bank workers won’t be able to prove your creditworthiness. They must ensure your ability to repay the loan based on previous loan repayments.

The size of the loan

If you want to receive a large sum of money, then lending companies will charge you higher interest rates. It works on the principle: the smaller the loan, the less interest you have to pay.

Employment and income sources

Borrowers must have an official employment place and stable income to be eligible for receiving the loan. Unemployed, self-employed borrowers put lending companies at risk of default on repayments. So, you should prove your ability to pay off the loan on time by providing this important information.

Term length

Short repayment duration means you will get rid of the loan quickly, and thus interest rates will be lower.

The number of scheduled repayments

Borrowers who make monthly repayments will be charged higher interest rates than those with annual or semiannual repayment plans.

Co-sign loans

Borrowers avail of this option to increase the chances of getting the loan by involving the person with a good or excellent credit score. This factor will also be decisive when defining the amount of interest rates.

Inflation in the country

When looking at it from an economic perspective, inflation affects the interest rate levels directly. When inflation rises, lenders unwilling to lose their assets also raise interest rates to make up for the decrease in the value of money.

Hence, there are fundamental aspects that influence interest rate fluctuations.

How to Choose the Best Interest Rates on a Loan?

Choosing the best interest rates on a loan can be quite a challenging task. Lending companies provide a wide range of different offerings for borrowers, so it can be hard to make a balanced decision. So, there are some pieces of advice for choosing the best interest rates:

1. Compare interest rates at different places. You can visit the websites of lending companies or contact customer support workers for detailed information.

2. Choose from two interest rate types. First, there are fixed and variable interest rates. In the first case, this percentage remains the same during the repayment term. In contrast, the variable interest rate can change due to an underlying benchmark or index that fluctuates constantly. So, you can opt for the most comfortable and convenient loan type.

3. Use the interest rates calculation method. This way, you will understand better how interest rates are defined by making your own calculations.

4. Apply for secured loans. This loan type requires collateral to secure the loan. If the borrowers fail to repay the loan, lenders can take away physical assets like a home or vehicle as compensation. Collateral serves the role of a backup plan for lenders, which is why they will charge their clients with lower interest rates.

5. Choose shorter repayment terms. Loans with short terms have lower interest rates, so don’t take loans over a long period if you are unwilling to pay high charges.

So, all these tips will help you find the best interest rates and get the loan with the best terms and conditions.

Does a Bad Credit Score Affect the Interest Rate?

Bad credit is a key factor when it comes to defining interest rates. Lending companies impose higher charges for this category of borrowers as a punishment for their poor credit score. So, people with bad credit score should be ready to pay more for their loans. However, considerable sums of money can become the reason for default on repayments. Hence, people with bad credit score should think carefully before taking this step and estimate their chances of paying off the loan on time.


Interest rate is a crucial aspect in the whole process of taking out the loan, so borrowers should not overlook it. It basically defines the amount of money you should return to the lending company.

This article explains how interest rates work and why lending companies impose them on borrowers. Now you know how to calculate them and choose the best options and offerings when applying for a loan.

Frequently Asked Questions:

  • What are interest rates today?

Lending companies define specific interest rates for every loan type. For example, borrowers applying for home loans are charged with an average of 5-6 % of interest rates.

  • What happens when interest rates rise?

If interest rates increase, the loan gets more expensive. In addition, it means that you will have to pay more charges over the initial amount of the loan.

  • How to schedule your repayment?

You can choose your own repayment plan. For example, lenders can offer you to make annual, semiannual, or monthly scheduled repayments. So it would be best if you defined what options will be comfortable and convenient for you to make paying off the loan less stressful.

  • How Does a Loan Interest Calculator Work?

You can quickly compute loan interest if a lender employs the simple interest technique. To determine the total interest cost, you will need the principal loan amount, the interest rate, and the loan term or the time you borrow the loan.

There is a standard formula for all loan types:

Principal loan amount × Interest rate × Time = Total interest rate

Let's look at a simple example to make all points clear.

For example, you submit an application for a $10,000 loan with a five-year term and a 5% interest rate. Then, using the formula, you should perform a straightforward calculation. It looks as follows:

$10,000 (principal loan amount) × 5/100 (Interest rate) × 5 (Time) = $2500

  • When Does Student Loan Interest Start Again?

Since March 2020, federal student loan payments have been stopped. There are no longer any payments due, no interest is accruing, and all collection efforts have been put on hold. However, this administrative forbearance is scheduled to end on December 31, 2022, so all payments will start again on January 1.

The forbearance period is scheduled to end on December 31, so borrowers who have yet to make payments must prepare to start doing so. According to the Department of Education, debtors will get a billing statement at least 21 days before the first payment is due, along with information and resources about starting payments again.

Meanwhile, you can check the websites of your loan servicer and the Federal Student Aid office to ensure your contact information is current so you'll be informed when payments start again.

  • How Does Interest Work on a Car Loan?

For auto loans, most lenders employ variable interest. Each month, interest is calculated based on the principal or the amount you owe. As you pay down your loan, you will spend less on interest, and more will go toward the principal. Throughout the loan, interest is evenly amortized or paid off. Precomputed interest is used less frequently on vehicle loans for borrowers with poor credit. The lender will compute the total interest paid during the loan term. The sum is divided among your monthly payments and added to the principal. You will pay higher interest at the start of your loan because interest is not amortized equally.

Simple and precomputed interest is the same if you intend to avoid paying off your loan early. With a simple interest vehicle loan, you will save more money if you pay off your loan early.

  • What Is the Average Interest Rate on a Home Loan?

When calculating the overall cost of borrowing, your interest rate is crucial in addition to the loan amount. Generally speaking, you will pay a higher interest rate if your credit score is lower. It would help if you also decided whether the interest rate on your loan is fixed or variable. If it is inconsistent, your interest expenses may change throughout your loan and impact your overall cost of borrowing.

According to a nationwide survey of major lenders, the benchmark fixed rate for 30-year mortgages is currently around 7%, its highest level in 20 years. This came about as the Federal Reserve followed through on its pledge to increase rates again at its November meeting. Although the federal policy doesn't directly affect fixed mortgage rates, the Central Bank has some influence over the 10-year Treasury yields, which influence the movement of fixed mortgage rates. However, the Fed's policies impact home equity products and adjustable-rate mortgages (ARMs).

  • Which Loan Type Provides Interest Subsidy?

Education loans for students from minority cultures who are studying abroad are loans that offer reduced interest rates. In the case of a subsidized direct loan, the lender or the government (in the case of Federal Direct Subsidized Loans, also known as Subsidized Stafford Loans) will cover your interest costs. At the same time, you can put the loan into deferment if you're enrolled in school (at least half-time) during the grace period following graduation.

Jonah Collins
Written by
Jonah Collins
Loans, Mortgage
Jonah Collins is a personal loans writer for Empire Finance. Backed by Master's of Science in Finance from Bournemouth University, he has hands-on experience as an investor and trader, along with editing and writing experience in finance, investments.