The individual demand curve represents the quantity of a good that a consumer will buy at a given price, holding all else constant. For example, consumer A might buy 2 orange at RS. 10 each, 4 oranges at Rs. 7 each, and 6 at Rs 4 each, while consumer B might buy 3 oranges at Rs. 10, 6 oranges at Rs 7, and 7 at Rs 4 . When charted on a graph with price on the vertical axis and quantity purchased on the horizontal axis, these points form the individual demand curves for consumers A and B.

Market Demand Curve:

The market demand curve is the sum of all the individual demand curves in the market. If the entire market consisted of only the two consumers mentioned above, the total demand for oranges at a price of Rs 10 would be 5 oranges, because A would buy 2 and B would buy 3 oranges. At a price Rs 7, the market demand would be ten oranges, summing A's 4 oranges and B's 6. For a single good, adding all the individual demand curves of the millions of consumers in the market makes the total market demand curve.