For calculating the retirement age, you can subtract your age from your expected or targeted age of retirement, while the inflation could be bracketed between 4-6 per cent per annum. The monthly expenses should include the inflated value of current expenses. After considering these three factors, a woman should consider the estimated return to achieve the desired retirement corpus. The returns will depend upon the kind of asset allocation they choose for their investment. If it is aggressive, the expected return can be around 12-14 per cent, for a moderate return, it can be around 10-12 per cent, and for a conservative return, it can be around 8-10 per cent.