Individual Demand and Market Demand:

When we say the demand for a commodity it means the "market demand" for that commodity. Since individuals consume the commodity, we may talk of individual demands too.

The Individual demand for a commodity is the quantities that would be purchased by an individual consumer of the commodity at a given set of prices of the commodity, when all other factors influencing demand remain unchanged. For a given set of prices for the commodity, individuals make their purchases, the set of prices and the corresponding quantities purchased by this individual consumer represents his/her individual demand.

The market demand for a commodity on the other hand is the total quantities that would be purchased by all individual consumers of a commodity at the same given set of prices, when all other factors remain unchanged; Market demand reflects the total demand of all individuals consuming the commodity. A market demand is a horizontal summation of all individual demands for a commodity.