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# How to Build an Interest Calculator in Excel

Updated June 18, 2018

Microsoft Excel is a popular spreadsheet program that can be used for a variety of calculations. Using Excel, you can build an interest calculator so that you can quickly determine how much interest will accrue on your account. This calculator will allow you to adjust the different components--the interest rate, number of compounding periods per year, years in the account and the amount of the account--to see how slight changes may affect the total amount of interest that accrues.

Label cell A1 "Balance," cell A2 "Annual Interest Rate Percentage," cell A3 "Compounding Periods Per Year," cell A4 "Time in Years," cell A5 "Periodic Rate," cell A6 "Number of Periods" and cell A7 "Total Interest."

Enter the balance of your account in cell B1, the annual interest rate expressed as a percentage in cell B2 and the number of times interest is compounded each year in cell B3.

Type in the formula "=B2/B3/100" in cell B4 to calculate the periodic interest rate expressed as a decimal rather than a percentage. After you enter this formula, Excel will automatically calculate the rate and display it in cell B4.

Enter the formula "=B4*B3" in cell B5 to calculate the total number of compounding periods based on the number of years the money is left in the account and the number of compounding periods per year. After you enter this formula, Excel will automatically calculate the number of periods and display it in cell B5.

Enter the formula "=(B5+1)^B6*B1-B1" in cell B6 to calculate the total interest that accrues on your account over the given time period. This formula takes into consideration interest compounding. After you enter this formula, Excel will automatically calculate the total interest and display it in cell B6.