The Compound Interest Calculator visually shows the dramatic effect that compounding can have on investments. Adjust the monthly savings, interest rate, and starting age to see how money grows over time.

Key Concepts

Investing, Interest, Compound Interest, Savers


The Benefits of Investing Early

The students will see how compounding returns make investing at a young age pay off.

Grades 9-12


Opportunity Cost

Consumers are faced with tough choices because so many innovative and exciting products and services are available. Therefore, engraining a decision-making process that includes considering of opportunity cost is necessary to shape future consumer behavior.

Grades 9-12

Loan Amortization - Mortgage

How to amortize a loan using an Excel spreadsheet.

Grades 9-12

Calculating Simple Interest

How do banks calculate the amount of interest paid on a loan? In this lesson, students will view a Livescribe Pencast to learn how to find the dollar amount in interest that is due at maturity. This lesson uses different time periods such as days, months, and years in the calculation as well as...

Grades 6-8, 9-12

Work, Earnings and Economics: Using 'Lyddie' by Katherine Paterson

To get started, the students will read Lyddie, a novel by Katherine Paterson. The novel is set mainly in Lowell, Massachusetts, in the 1840s. In Lowell the main character, 13-year-old Lyddie Worthen, works six days a week, from dawn until dusk, running weaving looms in a murky dust-and lintfill...

Grades 6-8

You Can BANK on This! (Part 3)

Building on the first two lessons in the series, this lesson deals with savings and interest.

Grades 3-5


  • “The compound interest example need not end at age 63. Today's school children will have to work until at least age 67 to collect full Social Security retirement benefits and are not likely to have a defined benefit pensions.”

    E. Elmore, Pomona, NJ   POSTED ON September 19, 2010

  • “I wish this calculator supported four-digit monthly savings!”

    Emily B., lincoln, NE   POSTED ON December 2, 2010

  • “This calculator is amazing. It helped me do my assignment and it is fun to play with.”

    Deazie V., Riverton, WY   POSTED ON December 3, 2010

  • “Who else set the age to 1, and everything else all 9s so you can watch the calculator flip out?”

    J. W., Sacramento, CA   POSTED ON July 19, 2011

  • “How often is interest being compounded? Can it be changed?

    EconEdLink: Her is a link to a Wikipedia article on Compound Interest.

    Lisa S., Kokomo, IN   POSTED ON June 11, 2012

  • “This calculator is dramatic and makes the point very clearly. Now you need to develop a similar calculator that demonstrates the effect of making the minimum payment on a credit card loan on the amount of interest paid and the time it takes to repay the loan.”

    Jim C., San Bernardino, CA   POSTED ON July 15, 2014

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