How to calculate capital gain income on sale of property

Gain = Net sale consideration - Indexed cost of acquisition

Net sale consideration = sale price - commission = 31.11L - 85K = 30.26L

Cost of acquisition = you can take fair market value as on 01.04.2001 as cost of acquisition (or) Purchase cost on 1985 which ever beneficial to you. but make sure when you take FMV use CII in the year of 2001-02 and if you don't opted FMV on 01.04.2001 then make sure use of CII for the year 1985. 

Determine your realized amount. This is the sale price minus any commissions or fees paid. Subtract your basis (what you paid) from the realized amount (how much you sold it for) to determine the difference. If you sold your assets for more than you paid, you have a capital gain.

In case of short-term capital gain, capital gain = final sale price – (the cost of acquisition + house improvement cost + transfer cost). In case of long-term capital gain, capital gain = final sale price – (transfer cost + indexed acquisition cost + indexed house improvement cost).