How is market size calculated?

Market size refers to the total revenue generated through the sales of a particular good or commodity. The most basic methodology is to multiply customer base with its wallet share for a typical customer. For instance, to calculate market size of toothpaste in India, we need to find the product of the number of toothpaste buyers across India with the price of toothpaste. A more accurate estimate can be found by segmenting the customer base as per income or geography, as they dictate the money spent on a particular commodity.