Calculate Compound or Simple Interest

Original Size

Money, in any form (cash, investments, receivables, etc.) will have a different value tomorrow or next month or next year than it does today. Even money stuffed in a mattress won't have the value in a year from now as it does today. That value is known as the "future value."

You must enter either a "Starting Amount" (the cash-on-hand) or the "Regular Contribution Amount" or both. Set how often you add to your investment by setting the "Contribution Frequency". If you set the "Contribution Frequency" to monthly and enter 120 for "Number of Contributions" then the "Future Value" will be for the date 10 years from the "First Contribution Date" (120 monthly contributions = 10 years).

A note or two about "Compounding Frequency". Selecting he "Exact/Simple" option sets the calculator so it will not compound the interest. Also, the exact number of days between withdrawal dates is used to calculate the interest for the period. The "Daily" option uses the exact number of days between dates, but daily compounding is assumed. (The interest earned each day is added to the principal amount each day.) The "Exact/Simple" compounding option is the most conservative setting. That is, using it will result in the lowest future value. Daily compounding will result in nearly the greatest future value (except for "Continuous Compounding".

The other compounding frequencies are based on periods of time other than days. Each period is assumed to be of equal length for the purposes of interest calculations. That is, assuming a balance of $10,000, the interest earned for January will be the same interest earned for February given the same interest rate.

NOTE: The future value maybe lower than the value reflected today — think inflation. To reflect that fact, simply use a negative interest.