Calculation of Capital Gains

[Sam Josh]

How are capital gains calculated on investment properties? Is the tax levied on Selling price minus purchase price or does the seller get exemption on selling costs such as broker fees? For example I buy a property for 100k, sell it for 120k. I incur 6k to sell the property. Am I taxed on 20k or 14k. The latter accounting for exclusion of selling costs.