Calculates the present value of an annuity or the present value of a growing annuity.
Where pv = present value, pmt = payment, rate = rate per period and nper = number of periods.
pv = - ( pmt / rate ) * [ 1 - [ 1/(1 + rate) ]^nper ]
Note: leave the Growth Rate per Period blank or 0 to calculate annuity without growth.
Note that we use the convention that either the present value or payment will be a negative value.
Where pv = present value, pmt = payment, rate = rate per period, growth_rate = growth rate per period for growth_rate < rate and nper = number of periods.
pv = - [ $pmt / ($rate - $growthrate) ] * ( 1 - [ (1 + growthrate)/(1 + rate) ]^nper )
Note that we use the convention that either the present value or payment will be a negative value.
Rate per Period is the interest rate for each payment period. Make sure that you are consistent with the units (months, years or quarters) you use for specifying Rate per Period.