Money solves the problems that the barter system creates. The functions of money include:

• Medium of Exchange
• Store of Value
• Unit of Account
• Standard of Deferred Payment

What is a Medium of Exchange?

First, money serves as a medium of exchange, which means that money acts as an intermediary between the buyer and the seller. Instead of exchanging accounting services for shoes, the accountant now exchanges accounting services for money. The accountant then uses this money to buy shoes. To serve as a medium of exchange, people must widely accept money as a method of payment in the markets for goods, labor, and financial capital.

What is a Store of Value?

Second, money must serve as a store of value. In a barter system, we saw the example of the shoemaker trading shoes for accounting services. However, she risks having her shoes go out of style, especially if she keeps them in a warehouse for future use—their value will decrease with each season. Shoes are not a good store of value. Holding money is a much easier way of storing value. You know that you do not need to spend it immediately because it will still hold its value the next day, or the next year. This function of money does not require that money is a perfect store of value. In an economy with inflation, money loses some buying power each year, but it remains money.

What is a Unit of Account?

Third, money serves as a unit of account,  which means that it is the ruler by which we measure values. For example, an accountant may charge $100 to file your tax return. That $100 can purchase two pair of shoes at $50 a pair. Money acts as a common denominator, an accounting method that simplifies thinking about trade-offs.

What is a Standard of Deferred Payment?

Finally, another function of money is that it must serve as a standard of deferred payment. This means that if money is usable today to make purchases, it must also be acceptable to make purchases today that the purchaser will pay in the future. Loans and future agreements are stated in monetary terms and the standard of deferred payment is what allows us to buy goods and services today and pay in the future. Thus, money serves all of these functions— it is a medium of exchange, store of value, unit of account, and standard of deferred payment.