Capital Gains Tax Mrs. Renée Short asked the Chancellor of the Exchequer what is the calculation of capital gains tax chargeable on a house purchased for £200,000 and sold for £600,000. Mr. Robret Sheldon Assuming that none of the capital gains tax exemptions or reliefs apply; and that the house was acquired on or after 6th April 1965, the tax would be £120,000, subject to allowance of the incidental costs of acquisition and disposal and the cost of additions and improvements.