You can calculate future value with compound interest using this formula: future value = present value x (1 + interest rate)n. To calculate future value with simple interest, use this formula: future value = present value x [1 + (interest rate x time)].
In the future value formula, n stands for the number of interest-compounding periods that occur during a specified time period. For instance, if you're calculating an investment's worth after five years, and interest on the investment is compounded annually, n would be 5 in the equation.
Depending on the model, your calculator might be equipped with a built-in FV calculation. For instance, on the Texas Instruments 84 model (the most popular calculator for math and finance classes), you can find the formula under the calculator's finance section. Alternatively, if you have a graphing calculator that can perform more complex math functions, just enter the numbers and run the calculation yourself.
For example, if you're trying to calculate the future value of a $500 investment with a 5% compounding annual interest rate over a period of 10 years, you'd key this into your graphing calculator:
You can also find a variety of future value calculators online.