FutureValue Command
 FutureValue( <Rate>, <Number of Periods>, <Payment>, <Present Value (optional)>, <Type (optional)> )

Returns the future value of an investment based on periodic, constant payments and a constant interest rate.

<Rate> Interest rate per period.

<Number of Periods> Total number of payment periods in an annuity.

<Payment> The amount paid in each period.

<Present Value (optional)> Total amount that a series of future payments is worth now. If you do not enter a value, it is assumed to be 0.

<Type (optional)> Indicates when payments are due. If you do not enter a value or you enter 0 the payment is due at the end of the period. If you enter 1 it is due at the beginning of the period.

FutureValue(10%/12, 15, 200, 0, 1)
yields a future value of 3207.99.
Make sure that you are consistent about the units you use for 
For all arguments, cash paid out is represented by negative numbers and cash received by positive numbers. 
See also Payment, Rate, Present Value and Periods commands. 