What is Surplus in Economics?

When the price is above the equilibrium price, the quantity supplied exceeds the quantity demanded. There is excess supply or a surplus. Suppliers will lower the price to increase sales, thereby moving toward equilibrium.

In mainstream economics, economic surplus, also known as total welfare or total social welfare or Marshallian surplus (after Alfred Marshall), is either of two related quantities:

• Consumer surplus, or consumers' surplus, is the monetary gain obtained by consumers because they are able to purchase a product for a price that is less than the highest price that they would be willing to pay.
• Producer surplus, or producers' surplus, is the amount that producers benefit by selling at a market price that is higher than the least that they would be willing to sell for; this is roughly equal to profit (since producers are not normally willing to sell at a loss and are normally indifferent to selling at a break-even price).

A surplus describes the amount of an asset or resource that exceeds the portion that's actively utilized. A surplus can refer to a host of different items, including income, profits, capital, and goods. In the context of inventories, a surplus describes products that remain sitting on store shelves, unpurchased. In budgetary contexts, a surplus occurs when income earned exceeds expenses paid. A budget surplus can also occur within governments when there's leftover tax revenue after all government programs are fully financed.  

A surplus is when you have more of something than you need or plan to use. For example, when you cook a meal, if you have food remaining after everyone has eaten, you have a surplus of food. You can choose to throw the food out, stockpile it, or try to find someone else, like a neighbor, who wants to eat the food.