What is the calculation for consumers surplus?

Consumer Surplus = the difference between what consumers are willing to pay and what they actually pay for a good or service. It is hard to explain this thru formula as it require a long explanation and debrief. Essentially it is represented by a triangle, and the surplus is calculated thru the formula to calculate a Triangles height. That is (BASE x HEIGHT)/2 I have attached a link below. Please refer it for details.