Simple Interest Calculator

Shawn Plummer

CEO, The Annuity Expert

Navigating the world of finance can be challenging, especially when understanding how interest rates work. But don’t worry; we’ve got you covered! In this guide, we’ll introduce you to simple interest and provide a step-by-step guide on using an online simple interest calculator. Whether saving money or paying off a loan, understanding how simple interest works will enable you to make better financial decisions. So, let’s dive in and explore this essential financial tool together.

Simple Interest Calculator

What is Simple Interest?

Definition of Simple Interest:

Simple interest is the basic type calculated only on the original principal amount. In other words, it does not consider any interest earned or paid on previous interest (compound interest). It is commonly used in short-term loans and investments where interest accrues over a fixed period.

Helpful Tool: Compound Interest Calculator

Simple Interest Formula:

The simple interest formula is expressed as I = P * R * T, where:

  • “I” represents the interest amount
  • “P” stands for the principal amount (the initial sum of money)
  • “R” denotes the interest rate (expressed as a decimal)
  • “T” signifies the time period (in years)
Simple Interest Calculator

Benefits of Using a Simple Interest Calculator

Accurate Calculations:

A simple interest calculator ensures your calculations’ accuracy, eliminating potential human errors. This precision is vital when making informed financial decisions, as a small mistake can have significant consequences.


A simple interest rate calculator speeds up determining interest amounts, freeing your valuable time for other essential tasks.

Easy Comparison:

A simple interest calculator lets you quickly compare different loan or investment options, enabling you to choose the most suitable option for your financial situation.

How to Use a Simple Interest Calculator

Input the Principal Amount:

Start by entering the initial sum of money you are investing or borrowing.

Enter the Interest Rate:

Next, input the annual interest rate, expressing it as a decimal. For example, if the interest rate is 5%, enter 0.05.

Input the Time Period:

Finally, enter the time period in the years for which the interest will be calculated.

Calculate the Simple Interest:

Once you have input all the required information, the calculator will determine the simple interest amount based on the given parameters.

How To Calculate Interest

Practical Applications of Simple Interest Calculations

Savings Accounts:

Understand the interest your savings account will earn over a specific period, helping you plan for future expenses or financial goals.

Personal Loans:

Determine the total interest payable on a short-term loan, allowing you to make informed decisions about repayment schedules and affordability.


Calculate the returns on short-term investments, enabling you to evaluate the profitability of different investment options.

Limitations of Simple Interest Calculations

Not Suitable for Compound Interest:

Remember that a simple interest rate calculator cannot be used for calculating compound interest, which is more commonly used in long-term loans and investments.

Does Not Account for Additional Fees:

Simple interest rate calculators only focus on the interest component and do not include other fees or charges associated with a loan or investment.

Earn The Highest Interest Rates On Savings Today

Fixed annuities are almost identical to Certificates of Deposit (CDs) accounts and provide higher interest rates and penalty-free withdrawals for income.

TermInsurance CompanyAPY
N/AMoney Market Account – Optimum Bank5.26%
N/AMoney Market Account – FVC Bank5.26%
N/ASavings Account – CloudBank 24/7 5.26%
12 MonthsBread Savings CD5.50%
48 MonthsClear Spring Fixed Annuity5.15%
5 YearsAthene Fixed Annuity5.30%
10 YearsEquitrust Fixed Annuity6.00%
*Fixed annuities are only for saving money to use in retirement.

Disclaimer: This is a review. The Annuity Expert is not associated with a bank or credit union. However, fixed annuities are sold at most financial institutions. We aim to help you find the highest interest rates for your retirement savings. We may receive a small referral fee if you purchase something using a link in this guide.

Find And Compare The Highest Interest Rates

Find the highest interest rates for your savings, ranging from 3 months to 10 years, all in one place.


Understanding how simple interest works is essential for making sound financial decisions. A simple interest calculator is an invaluable tool that simplifies the process of calculating interest amounts, saving you time and ensuring accuracy. Following our step-by-step guide, you can quickly determine the interest on savings accounts, personal loans, and short-term investments, enabling you to compare different financial options and make informed choices. Remember

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Shawn Plummer

CEO, The Annuity Expert

I’m a licensed financial professional focusing on annuities and insurance for more than a decade. My former role was training financial advisors, including for a Fortune Global 500 insurance company. I’ve been featured in Time Magazine, Yahoo! Finance, MSN, SmartAsset, Entrepreneur, Bloomberg, The Simple Dollar, U.S. News and World Report, and Women’s Health Magazine.

The Annuity Expert is an online insurance agency servicing consumers across the United States. My goal is to help you take the guesswork out of retirement planning or find the best insurance coverage at the cheapest rates for you. 

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