Wolfram Research
Wolfram Math World: Simple Interest
This math site explains and defines the concept of "simple interest" and gives a formula for finding this value in terms of time and rate.
University of Toronto (Canada)
Answers and Explanations Simple and Compound Interest
If a bank account produces "simple interest", the interest is paid directly and does not become part of the account's interest-bearing balance. That balance remains constant, and it's easy to figure out how much money you earn. This site...
Other
Credit Karma: Simple Loan Payment Calculator
If you enter the values for a simple loan payment, it will give the monthly payments. You will need to know the principal, interest, and amount of time in years.
Annenberg Foundation
Annenberg Learner: Math in Daily Life: Savings and Credit
A brief article explaining the basics about savings accounts and two kinds of interest: simple and compound. Also learn about managing your credit and credit card debt. Click on "Know the Terms: How to Manage Your Credit Cards" to read...
National Council of Teachers of Mathematics
The Math Forum: Interest Rates
This Dr. Math site asks about simple interest and its effect on the repayment of a loan.
University of Nebraska Omaha
Ec Ed Web: M&m Interesting [Pdf]
This site from the University of Omaha provides a lesson plan indicated for 6-8th grades. "During this lesson, students use the economic concepts of trade-offs and opportunity costs to decide between savings accounts with simple interest...
Other
Financial Pipeline: Interest Compounding
This page gives a summary of compounding interest and distinguishes it from simple interest.
Calculator Soup
Calculator Soup: Simple Interest Calculator a = P(1 + Rt)
This simple interest calculator calculates an accrued amount that includes principal plus interest.
Mocomi & Anibrain Digital Technologies
Mocomi: Simple Interest and Compound Interest
Explains simple and compound interest with formulas and examples.