Material balances are a method of economic planning where material supplies are accounted for in natural units (as opposed to using monetary accounting) and used to balance the supply of available inputs with targeted outputs. Material balancing involves taking a survey of the available inputs and raw materials in an economy and then using a balance sheet to balance the inputs with output targets specified by industry to achieve a balance between supply and demand. This balance is used to formulate a plan for resource allocation and investment in a national economy.