Opportunity cost is the value of the next best alternative that you give up when you make a decision.
Think of it as the pizza slice you leave on the plate when you choose a burger 🍕🍔.
Because resources (time, money, labour, etc.) are scarce, every choice involves a trade‑off.
Understanding opportunity cost helps you predict how consumers, workers, firms and governments will behave.
Consumers decide how to spend their limited income.
When you buy a new phone, the opportunity cost is the other things you could have bought with that money (e.g., a weekend trip, a new book, saving for a car).
Example: If you spend \$200 on a concert ticket, the opportunity cost might be a \$150 vacation + $50 for a new video game.
Workers choose how to allocate their time between work and leisure.
The opportunity cost of working an extra hour is the leisure time you lose.
Formula: \$OC_{\text{time}} = \text{Value of leisure lost}\$
If you earn \$15 per hour, the opportunity cost of an extra hour of work is \$15 worth of free time.
Firms decide how to use their resources (land, labour, capital) to produce goods.
The opportunity cost of using a machine for product A is the profit that could have been earned by using it for product B.
Example: A factory can produce either 100 units of T‑shirts or 50 units of hoodies.
If it chooses T‑shirts, the opportunity cost is the 50 hoodies it could have made.
Governments allocate public resources (tax revenue) to services like education, health, defence.
The opportunity cost of spending on defence is the education or infrastructure that could have been funded instead.
Illustration: If a country spends \$1 billion on a new highway, the opportunity cost is the \$1 billion that could have been used to build hospitals.
| Tip | Why It Helps |
|---|---|
| Identify the decision made. | Shows you understand the context. |
| State the next best alternative. | Directly answers the opportunity cost. |
| Use simple examples or analogies. | Makes your answer clear and memorable. |
| Show the calculation if numbers are given. | Demonstrates quantitative skills. |
A student has 10 hours of free time. She can either study for an exam (worth 5 marks) or watch a movie (worth 0 marks).
What is the opportunity cost of watching the movie?
Answer: The opportunity cost is the 5 marks she could have earned by studying.
Formula: \$OC = 5 \text{ marks}\$.