Home » Bookkeeping articles » Simple and Compound Interest Calculator

# Simple and Compound Interest Calculator

August 2, 2024
Bill Kimball

While you may not consider \$310 a huge difference, this example is only a three-year loan; compound interest piles up and becomes oppressive with longer loan terms. Let’s say that you are borrowing \$10,000 from Bank A to finance an automobile purchase. It’s a simple interest loan with a rate of 5% and a term of 5 years.

## What is the difference between simple and compound interest?

The answer depends on the interest rate, deposits and the amount of time given to earn interest. Also, because of compounding, the more often interest is deposited into a savings account, the more the overall balance will grow. An account that compounds daily can grow more than one that compounds less frequently, such as once a month. To increase your bank balance faster, put your money in an account with a high yield that compounds frequently. You can calculate interest for months, days, years, or any other period.

## What is principal in simple interest?

The prime interest rate is what banks charge their best customers. In other words, it’s the lowest possible rate on a given day. This rate is typically available only to institutional customers. The average consumer pays the prime rate plus another rate based on their riskiness as a borrower. But what if you were to leave that extra cash in the account? If you have \$1 million in an account that earns 5% interest compounded monthly, you would earn \$51,161.90 after one year.

## Loan Calculators

If you want to assume that interest from the previous periods influences the original amount, you should apply compound interest. Our partners cannot pay us to guarantee favorable reviews of their products or services. Since simple interest is calculated only on the principal, it is easier to determine than compound interest. As a reminder, simple interest paid or received over a certain period is a fixed percentage of the principal amount that was borrowed or lent. Enter the principal amount, interest rate, time period, and click ‘Calculate’ to retrieve the interest. Now you know what is simple interest and how to calculate its value.

1. The principal, or principal amount, is the initial amount of money lent or invested.
2. In finance, interest rate is defined as the amount that is charged by a lender to a borrower for the use of assets.
3. Just provide the interest percentage, and you’ll know how much that loan costs.
4. Compound interest is a bit more complicated and a bit more valuable.
5. But keep in mind that balances above \$250,000 may not be federally insured.

## What Are Some Financial Instruments That Use Simple Interest?

He is a CFA charterholder as well as holding FINRA Series 7, 55 & 63 licenses. He currently researches and teaches economic sociology and the social studies of finance at the Hebrew University in Jerusalem. We believe everyone should be able to make financial decisions with confidence.

## You’re our first priority.Every time.

This value tells you what is the interest rate on a yearly basis and thus helps you make the best (i.e., the most reasonable) financial decision. If you are not sure how to do this, read the APY calculator description, where everything is explained in detail. Note here that if you make a deposit in a bank (e.g., put money in your savings account), from a financial perspective, it means that you lend money to the bank.

But keep in mind that balances above \$250,000 may not be federally insured. Amounts above the insurance limit may not be covered in the event of a bank failure. You can enter a beginning balance and see how much interest you’ll earn over time, with or without contributions. You can also start with a \$0 beginning balance and see how fast you can build your savings with monthly or quarterly contributions. Simple interest is based on the original principal amount of a loan or deposit. Lowering the interest rate, shortening the loan term, or prepaying principal also has a compounding effect.

So it’s high time you become familiar with more complex concepts of financial mathematics. You wouldn’t get your \$4,166 every month, but you’d have 131 times more in the bank after 100 years. Note that since simple interest is calculated only on the original amount, it’s much easier to determine than compound interest. However, with our calculators, you won’t feel the difference. In the next sections, we will also show you some examples of simple interest calculations.

The information you need for any of these calculations is generally the same, but the math is a bit different for each. The APY accounts for compound interest, which is the interest you earn as your account grows due to interest payments. APY will be higher than your actual rate unless the interest is compounded annually, so APY can provide an inaccurate result when converting to a monthly rate. That said, APY makes it easy to quickly find out how much you’ll earn annually on a savings account with no deposits or withdrawals. Use this interest calculator to compare other contribution amounts and yields. An interest calculator computes how much interest you can earn over time in a savings account.

With credit cards, you can add new charges and pay off debt numerous times throughout the month. All of that activity makes calculations more cumbersome, but it’s still worth knowing how your monthly interest adds up. In other cases, your card issuer charges interest daily (so you’d want to calculate a daily interest rate—not a monthly rate). For example, you have monthly utility bills, food costs, or a car payment. Interest is also a monthly (if not daily) event, and those recurring interest calculations add up to big numbers over the course of a year. Whether you’re paying interest on a loan or earning interest in a savings account, the process of converting from an annual rate (APY or APR) to a monthly interest rate is the same.

You can use our mortgage calculator (below) to see how your principal payment, interest charges, taxes, and insurance add up to your monthly mortgage payment. Interest is the value that we add to a loan or a deposit to pay for the benefit of using someone else’s money over time. Simple interest is the easiest calculation, generally for short-term loans. Compound interest is a bit more complicated and a bit more valuable. Finally, continuously compounding interest grows at the fastest rate and is the formula that most banks use for mortgage loans.

Simple interest does not take into account the effects of compounding. In other words, with compounding, you earn the interest not only on the principal amount but also on the interest that was earned over the previous periods. It is essential information to know, as with compound interest you actually earn or pay more over the considered period. You can calculate simple interest by multiplying the account balance by the interest rate, and multiplying that by the number of time periods.

Whatever period you choose, the rate you use in calculations is called the periodic interest rate. You’ll most often see rates quoted in terms of an annual rate, so you typically need to convert to whatever periodic rate matches your question or your financial product. The interest rate is commonly expressed as a percentage of the principal amount (loan outstanding or value of deposit). In that case, it is called the annual percentage yield (APY) or the effective annual rate (EAR).

If you don’t let the principal payments vary, as in an interest-only loan (zero principal payment), or by equalizing the principal payments, the loan interest itself doesn’t compound. If you make partial payments to a simple interest loan, the payment will be applied to interest first, and any remainder will be used to reduce the principal. Simple interest usually applies to automobile loans or short-term personal loans. In the U.S., most mortgages on an amortization schedule also involve simple interest, although they can certainly feel like compound interest loans. For example, let’s say that a student obtains a simple interest loan to pay for one year of college tuition.

The difference between “just” interest and mortgage payment is simple — with the mortgage calculator, every month you repay a part of the principal and your loan balance gets lower and lower. With the simple interest calculator, only the interest is paid. Nothing changes with time, so we didn’t include a field that would specify your loan’s duration. Simple Interest is similar to Daily Simple Interest except that with the latter, interest accrues daily and is added to your account balance. Also, while loan balances on simple interest debt are reduced on the payment due date, daily simple interest loan balances are reduced on the day payments are received.

Just provide the interest percentage, and you’ll know how much that loan costs. Compound interest is often a factor in business transactions, investments, and financial products intended to extend for multiple periods or years. Typically, simple interest is used for loans of a single period or less than a year. The formula to determine simple interest is an easy one. Just multiply the loan’s principal amount by the annual interest rate by the term of the loan in years.