Opportunity Cost Calculator
Compare choices, investments, or production trade-offs to calculate opportunity cost — with clear visuals for every scenario.
Background
Opportunity cost is the value of the best thing you gave up when you made a choice. Resources — money, time, land, labor — are limited, so choosing one option always means giving up something else. Economists sum this up as "there's no such thing as a free lunch": every decision has a cost, even when no cash actually changes hands.
How to use this calculator
- Choose Compare Options when you're weighing 2 or more discrete choices, each worth a certain dollar amount (a job offer, a bonus, a weekend activity) — mark which one you picked, and it finds the best alternative you gave up.
- Choose Investment Growth when you're comparing two ways to grow the same money over time (stocks vs. savings, one fund vs. another) — it compounds both forward and shows the foregone future value.
- Choose Production Trade-off for the classic economics scenario: fixed resources that can produce more of one good only by producing less of another (like a factory or farm) — it calculates the marginal opportunity cost per unit.
- Click Calculate to see the opportunity cost, a supporting chart, and full step-by-step working.
How opportunity cost works
Opportunity cost is the value of the next best alternative you give up — not every alternative, just the single best one you didn't pick.
It applies even when no money changes hands. Spending an afternoon studying has an opportunity cost measured in whatever else you could have done with that time — working, resting, socializing.
Explicit costs are the direct cash outlays of a choice. Implicit costs are the foregone benefits of the road not taken — like the salary you don't earn while running your own business. Opportunity cost captures both.
On a production possibilities frontier (PPF), the opportunity cost of producing more of one good is the slope of the trade-off curve — how much of the other good you must give up per additional unit.
A negative "opportunity cost minus benefit" isn't a contradiction — it just means the option you chose was actually better than the alternative, so you came out ahead rather than behind.
Formula & Equations Used
Opportunity cost (general): OC = Value of best forgone alternative
Net advantage of your choice: Net = Value chosen − Value of best alternative
Compound growth: FV = P × (1 + r/n)^(n×t), where P is principal, r is the annual rate, n is compounding periods per year, and t is years.
Investment opportunity cost: OC = FV(alternative) − FV(chosen)
Marginal opportunity cost (PPF): OC of one more unit of A = |ΔB / ΔA|, measured in units of the other good.
Example Problems & Step-by-Step Solutions
These cover cases the Quick Examples chips above don't already demonstrate.
Example 1 — Three job offers
You're deciding between three summer jobs, each worth (in total pay) \$2,400, \$3,100, and \$1,800. You take the \$2,400 job because of the schedule. What's your opportunity cost?
Step: The best option you didn't take is the \(3,100 job. Opportunity cost = \)3,100. Net advantage = \$2,400 − \(3,100 = −\)700.
Result: Opportunity cost = \(3,100; you gave up \)700 in pay for the better schedule.
Example 2 — Monthly compounding
\$10,000 invested at 6% annual return, compounded monthly, for 5 years — vs. leaving it in a 0% checking account. What's the opportunity cost of not investing?
Step: FV = 10,000 × (1 + 0.06/12)^(12×5) ≈ \$13,488.50. Checking account stays at \$10,000.
Result: Opportunity cost of leaving it in checking ≈ \$3,488.50 in foregone growth.
Example 3 — A one-directional PPF move
A country produces 50 tanks and 200 tractors. It shifts resources to produce 80 tanks and 140 tractors. What's the opportunity cost of one more tank?
Step: ΔTanks = 80−50 = 30. ΔTractors = 140−200 = −60. OC per tank = |−60/30| = 2.
Result: Each additional tank costs 2 tractors of forgone production.
Example 4 — When the "best" option is the one you chose
Options worth \$500, \$900, and \$700 — you choose the \$900 option, the best one available. What's the opportunity cost?
Step: The best alternative you gave up is the \(700 option (the next-best after your own choice). Opportunity cost = \)700, not \$0.
Result: Even the best choice has an opportunity cost — here, \$700 — it's just smaller than choosing worse would have cost you.
Frequently Asked Questions
Isn't opportunity cost zero if I pick the best option?
No — opportunity cost is the value of the best alternative you gave up, and there's always a next-best option unless you had literally only one choice. Picking the best option just means your opportunity cost is as small as it could be, not zero.
What's the difference between opportunity cost and sunk cost?
Opportunity cost is forward-looking — what you give up by choosing one path over another right now. A sunk cost is money or effort already spent that can't be recovered, and it shouldn't factor into future decisions at all, unlike opportunity cost.
Does opportunity cost only apply to money?
No. Time, land, labor, and attention are all limited resources, so choosing how to spend any of them has an opportunity cost — the value of what else that resource could have produced.
Why does the production trade-off mode require one good to go up and the other down?
That's what a real trade-off along a production possibilities frontier looks like — resources are fixed, so producing more of one good is only possible by producing less of another. If both went up or both went down, you're not looking at a trade-off, just a change in overall efficiency.
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