Present value is the current value of a payment expected in the future based on a decrease in value caused by inflation.
Future Value is the amount of the payment in the future:
Interest is the expected rate of inflation per period.
Number of Periods how far in the future the payment will be received.
Example: If you were to receive $1000 five years from now and you expect the interest rate to be 3% then you would enter the following values:
Future Value: 1000
Interest: 3
Number of Periods: 5