What you'll learn

• What economists mean by money — and why it is more than banknotes and coins.
• The four key functions of money: medium of exchange, unit of account, store of value and means of deferred payment.
• How to apply these functions to real-life UK examples like contactless payments, savings, phone contracts and buy-now-pay-later.
• Common exam traps, especially confusing money with the payment method used to move it.

3.2.5.1 Functions and definition of money

Starting point: why money exists

Before money, people could use barter, which means swapping one good or service directly for another. For example, a baker might swap bread for a haircut.

The problem is that barter needs a double coincidence of wants: each person must want exactly what the other person is offering, at the same time. That is very inconvenient in a modern economy with millions of goods and services.

Money solves this by acting as something everyone is willing to accept in exchange.

“Generally accepted” is important. Something only accepted in one shop, or by one small group of people, is not usually money in the full economic sense.

The diagram below summarises the four functions of money and the idea that modern money includes more than cash.

The four functions of money

1. Money as a medium of exchange

A medium of exchange is something used to buy and sell goods and services.

When you buy a Greggs sausage roll, pay for a bus ticket, or tap your card in Tesco, money is helping the exchange happen. The seller does not need to want anything you personally produce — they accept money because they know they can use it elsewhere.

This is what makes a large, specialised economy possible. People can focus on one job, earn income, and use that income to buy the things they need.

2. Money as a unit of account

A unit of account is a common measure used to state prices and values.

In the UK, prices are usually measured in pounds sterling (£). This lets you compare very different things using the same unit: a £2 loaf of bread, a £9 cinema ticket, a £25 phone contract, or a £1,200 monthly rent.

Businesses also use money as a unit of account when recording revenue, costs and profit. Without a common unit, it would be much harder to compare options or keep financial records.

3. Money as a store of value

A store of value means money can be kept and used later.

If you receive £30 for a birthday and save it for next month, the money is storing value between now and then. This is much more useful than being paid in something perishable, such as fresh fruit, which might go off before you can use it.

However, money is not a perfect store of value. If prices rise, the same amount of money buys less than before. This became very clear during the UK cost-of-living squeeze in 2022–23, when food, energy and other prices rose sharply.

4. Money as a means of deferred payment

A means of deferred payment means money can be used to settle debts or payments at a future date. Deferred means delayed until later.

This matters for borrowing and credit. For example, if you take out a phone contract, the monthly payment is stated in pounds and paid later. If someone has a mortgage, the amount borrowed and the repayments are also measured and paid in money.

Buy-now-pay-later services are another modern example. They allow consumers to receive goods now and pay in future instalments. This can be convenient, but it can also encourage people to spend more than they can afford.

Money is more than banknotes and coins

When people hear “money”, they often think of cash: physical banknotes and coins. Cash is money, but it is not the whole story.

In a modern UK economy, much money exists as bank deposits. A bank deposit is money recorded in a bank account, such as the balance in a current account. You can use it to make payments by debit card, bank transfer, standing order, direct debit or contactless payment.

During and after COVID-19, many UK consumers used less cash and more contactless and online payments. That did not mean money disappeared — it meant people were increasingly moving bank deposits electronically.

A debit card is not itself money. It is a tool that gives instructions to move money from one bank account to another.

What counts as money?

To decide whether something is money, ask whether it is widely accepted for payments and debts.

Why this matters in the real economy

Money is not just an abstract idea. It affects everyday decisions.

For consumers, money makes it easier to compare prices, save for future spending, and use credit. But the rise of digital payments also raises ethical questions. Some people — including some elderly, rural or low-income consumers — may rely more heavily on cash. If shops, banks or public services move too quickly away from cash, those consumers can be excluded.

For businesses, money makes trading faster and record-keeping easier. A supermarket can price thousands of products in pounds, receive card payments quickly, and compare costs and revenues.

For the wider economy, trust in money is essential. If people stop believing that money will be accepted, or if inflation becomes very high, money becomes less useful as a store of value and unit of account.

Bringing the functions together

The four functions overlap in real life.

For example, imagine you buy a £4 meal deal using contactless payment:

• The £4 price shows money as a unit of account.
• The payment transfers bank deposits, so money acts as a medium of exchange.
• If the shop lets you pay later through an app or account, money becomes a means of deferred payment.
• If you saved that £4 from last week, money was also a store of value.

So in exam answers, do not treat the functions as completely separate worlds. A single situation can show more than one function of money.