Supply is a fundamental concept in economics that refers to the quantity of goods and services that producers are willing and able to offer for sale at various prices within a given period.

It represents the relationship between the price of a product and the quantity supplied. Generally as prices rise, producers are typically motivated to supply more goods or services to the market, increasing the quantity supplied. Conversely, when prices fall, producers may reduce the quantity supplied as it becomes less profitable.

Several factors affect supply, including input costs, technology, government policies, the number of suppliers, and future price expectations. Input costs, like raw materials and labor, significantly impact production expenses. Higher input costs tend to decrease supply, while lower input costs can increase it. Technological advancements can enhance production efficiency, leading to an increase in supply. Government policies, such as subsidies, taxes or regulations, shape supply dynamics. The number of suppliers in the market increases or decreases overall supply levels. Additionally, producers' expectations about future prices can influence current supply decisions. If higher price anticipated, producers might reduce current supply to sell more later, and vice versa. All these factors interact to determine how much producers are willing and able to supply at different price levels.

Understanding supply is essential as it helps individuals comprehend how businesses make production decisions and how changes in supply affect market equilibrium.