Calculating Inflation, retirement and cost of living adjustments over 30 years

[rbt]

Is this mathematically correct?


def inflation():
     start = int(str.strip(raw_input("How much money do you need each 
month at the start of retirement: ")))
     inflation = float(str.strip(raw_input("What will inflation average 
over the next 30 years(.03, .04, etc): ")))

     for x in xrange(30):
         start = start*inflation+start
         print start

inflation()