011 min
Opportunity Cost at a glance
- What it is: The benefit you would have had from the single best choice you did not make.
- The number that matters: A four-year US public degree costs about $47,800 in tuition, but the earnings a student gives up can be larger.
- Where it breaks: Adding up every rejected option overstates the cost. Only the best one counts.
021 min
The problem Opportunity Cost names
The mistake this concept names is treating the price of a choice as its whole cost.
OpenStax's Principles of Economics textbook gives a plain case. A company sends every employee on a two-day retreat. The budget shows a venue and an outside facilitator. It does not show the larger cost: for two days, nobody in the company does any other work.
The same gap appears in every choice with limited resources. A team that spends a quarter on one feature has not built the feature it would have built instead. Neither loss is recorded anywhere, so nobody argues about it in the meeting where the decision is made.
What it costs when missed: a project is approved because it "only" costs its budget. A better use of the same people and months is never compared against it. The decision looks cheap because part of its cost was never written down.
032 min
Understanding Opportunity Cost
Opportunity cost follows from one fact: resources used for one thing cannot be used for another at the same time. Money, hours, machine capacity and staff are all limited. So every "yes" is also a "no" to something else. The opportunity cost is the value of the best thing on the "no" side.
Three rules make the idea precise.
1. Only the next-best alternative counts. Suppose you could spend a Saturday on a paid shift, on study, or on rest. If you rest, the opportunity cost is whichever of the other two you valued more. It is not the sum of both, because you could never have done both.
2. Count explicit and implicit costs. An explicit cost is money you actually pay. An implicit cost is a benefit you give up without paying anything, such as a salary you no longer earn. Subtracting both from revenue gives economic profit. Accountants subtract only explicit costs, which gives accounting profit.
3. Measure the alternative net of its own cost. Suppose the best alternative would give you a benefit of $50 but cost $40 to get. Then you gave up $10 of value, not $50. This is the rule people break most often.
A hypothetical running example shows all three. A software engineer earning $150,000 a year leaves to run their own company, which pays them $60,000. The accounts record $60,000 of salary. But the engineer's best alternative was the $150,000 job, so $90,000 of the cost of their labour never appears in the books. If the company's accounting profit is $50,000, its economic profit is minus $40,000. The founder is worse off than in the job they left, before counting equity.
042 min
Why people overlook Opportunity Cost
If opportunity cost is simple arithmetic, why do people ignore it? The best-known evidence is a 2009 paper, "Opportunity Cost Neglect", by Shane Frederick and four co-authors in the Journal of Consumer Research.
Their argument: to count an opportunity cost, a buyer has to think of the alternative themselves. Nothing on the shelf lists it. So the authors predicted that simply naming the alternative would change choices, even though it adds no new facts.
It did. In one study, 150 Arizona State University students were offered a DVD at $14.99. When the option not to buy was worded as "Keep the $14.99 for other purchases" instead of "Not buy", the share who would buy fell. In the paper's words, describing the "Not buy" option as "Keeping money for other purchases" caused willingness to purchase to fall from 75% to 55%.
In a second study, 110 MIT MBA students chose between a $700 and a $1,000 stereo. Adding "leaving you $300 to buy CDs" to the cheaper option raised its share to 82%, against 59% in the control group. A third wording, "spend $300 more", named the same price difference but no alternative use for the money. It did not raise the cheaper stereo's share.
The practical reading: people accept the idea but do not think of the alternative unless prompted. This is a close relative of the framing effect, where the wording of equal options changes the choice.
051 min
Where Opportunity Cost comes from
The usual attribution is to the Austrian economist Friedrich von Wieser. His 1889 book Der natürliche Werth (Natural Value) treated the value of a resource as the value of what it could have produced elsewhere. His 1914 Theorie der gesellschaftlichen Wirtschaft (Theory of Social Economy) developed what is called the alternative-cost theory.
The English phrase itself is documented earlier than 1914. In January 1894 the American economist David I. Green published "Pain-Cost and Opportunity-Cost" in the Quarterly Journal of Economics. He argued that the cost of work is mainly the other work you cannot do, not the effort involved. In his words: "By devoting our efforts to any one task, we necessarily give up the opportunity of doing certain other things which would yield us some return."
A 2020 working paper by Sheetal Bharat at BASE University traces the idea further back, to Richard Cantillon, David Ricardo and John Stuart Mill. Bharat reports that a study of Wieser's works to look for the first formal definition of opportunity costs was unsuccessful. The fair summary: Wieser made the idea central to a theory of value. Green used the English name in print. Earlier economists used the reasoning without the label.
062 min
The numbers: the opportunity cost of a degree
College is the standard numeric case, because the largest cost is not on the tuition bill. OpenStax notes that college imposes both an out-of-pocket cost and an opportunity cost of lost earnings. Here is the arithmetic with real US figures.
Input 1, the explicit cost. The College Board reports average published tuition and fees of $11,950 for in-state students at US public four-year colleges in 2025-26.
Input 2, the implicit cost. The US National Center for Education Statistics (NCES) reports median earnings of $41,800 in 2022 for full-time workers aged 25-34 with only a high school education. That overstates what an 18-year-old would earn, so the table also shows a hypothetical case at half that wage.
| Cost item | Per year | Four years |
|---|---|---|
| Tuition and fees (explicit) | $11,950 | $47,800 |
| Forgone earnings, full $41,800 wage | $41,800 | $167,200 |
| Forgone earnings, hypothetical half wage | $20,900 | $83,600 |
| Total cost, half-wage case | $131,400 | |
| Total cost, full-wage case | $215,000 |
In the half-wage case, forgone earnings are 64% of the total ($83,600 ÷ $131,400). In the full-wage case they are 78% ($167,200 ÷ $215,000). Either way, the cost a student never receives a bill for is larger than the one they do.
Room and board are left out, because a person pays for food and housing whether or not they study. Part-time work would reduce the forgone earnings.
The calculation does not say a degree is a poor choice. NCES reports that bachelor's degree holders in the same age group earned 59% more. Opportunity cost gives you the full cost side. The decision still needs the benefit side, which is the job of cost-benefit analysis.
072 min
Opportunity Cost at national scale: queues and bombers
The degree example is one person's money and time. Two public cases show the same logic when the resource is shared across a country.
Airport security and travellers' time
After the September 2001 hijackings, the US added screening steps at airports. OpenStax's Principles of Economics estimates what that cost. It uses US Department of Transportation data of 895.5 million scheduled passengers in 2015 and assumes each spends an extra 30 minutes at the airport. It values that time at $20 an hour. The result is up to $8 billion a year. The textbook's conclusion is that the single biggest cost of greater airline security does not involve spending money. It is the opportunity cost of additional waiting time at the airport.
No government budget records that $8 billion.
Eisenhower's 1953 speech
On 16 April 1953, US President Dwight D. Eisenhower spoke to the American Society of Newspaper Editors. He stated the cost of military spending in the goods it replaced, not in dollars: "The cost of one modern heavy bomber is this: a modern brick school in more than 30 cities. It is two electric power plants, each serving a town of 60,000 population."
The variable that differs is who carries the cost, and in what unit. The airport cost is travellers' time, and no account records it. Eisenhower's cost is a budget line, restated as schools and power plants. Together they show two ways to make an opportunity cost visible. Convert time into money, or convert money into the specific things it would have bought.
081 min
How Apple's car project shows Opportunity Cost
On 27 February 2024, Apple told staff it was ending its electric car effort, known internally as Project Titan. NPR reported that the project was estimated to have cost Apple billions of dollars, with around 2,000 employees working on it. NPR also reported that hundreds of those employees would move to divisions working on artificial intelligence.
Apple did not publish its reasoning. But the reported move of staff shows the two costs the decision separated.
- The billions already spent are a sunk cost. They were gone whatever Apple chose next, so they should not have affected the choice.
- The next year of work from about 2,000 people was the opportunity cost of continuing. Every month those engineers spent on the car was a month not spent on the company's next-best project. The reports named that project: generative AI, where Apple was then seen as behind competitors.
The case also shows that opportunity cost changes over time. The car project did not have to get worse for continuing to become more expensive. It was enough for the best alternative use of the same engineers to become more valuable.
The question "have we spent too much to stop?" looks backwards. The useful question is "what would these people build if we stopped today, and is that worth more?"
092 min
What Opportunity Cost means for your work
The scenarios below are illustrative. Each shows a decision that changes once the alternative is named.
A product manager planning a quarter. The team has a fixed number of engineering weeks. A six-week integration request looks reasonable on its own. So the PM adds one line to the proposal. It says the same six weeks would otherwise ship the onboarding redesign. Now the review compares two concrete outcomes, not one outcome against nothing.
An engineer choosing build or buy. An internal logging tool would take two engineers three months. A hosted service costs $400 a month (hypothetical figure). The engineer's first comparison is salary against subscription. The better comparison adds what those six engineer-months would have built for customers. That is usually the larger number, and it is not in any budget.
A designer deciding on research. A two-week usability study delays a release by two weeks. The opportunity cost is two weeks of the feature's value in use. For a feature that is easy to change after launch, that often outweighs what the study would catch. For one that is hard to reverse, such as a pricing change, it rarely does.
A founder setting their own pay. A founder paying themselves far below their market salary is funding the company with the difference. Counting that gap as a cost shows whether the business earns more than the founder's best alternative job.
In each case, the change is small: name the alternative in writing, in the same unit as the proposal.
101 min
How to apply Opportunity Cost
Use this check on any decision that commits money, people or calendar time.
Write down the next-best alternative in one sentence.
Be specific: "the onboarding redesign", not "other work". Frederick's experiments found that people rarely do this unprompted.
Put both options in the same unit.
Use dollars, engineer-weeks, or customer outcomes, but the same one for both. Comparing "six weeks" against "$4,800" invites mistakes.
Measure the alternative net of its own cost.
Subtract what the alternative would have required. Its full benefit overstates what you lose.
Count only the best alternative.
Do not add together every option you turned down.
Include people's time at its full cost.
A person-week costs salary plus benefits plus the work it displaces.
Recheck at each planning cycle.
The best alternative changes as the market and the team change, so a choice that was right last quarter can be wrong now.
A one-line template makes step 3 hard to skip:
Choosing A over B costs us [B's benefit] minus [B's own cost], which is [the number].
112 min
When Opportunity Cost breaks
Opportunity cost is simple to state and easy to get wrong. The main failure modes, with the sign of each:
- Gross instead of net. Counting the alternative's full benefit and forgetting its own cost. The sign: an opportunity cost larger than the alternative could ever have returned.
- Summing every alternative. The sign: a cost figure that adds up options you could never have taken together.
- False precision. When the best alternative is itself uncertain, a single number hides a wide range. The sign: a cost quoted to the dollar for work nobody has scoped.
- Using it as a veto. Every choice has an opportunity cost, so the phrase can be used against any proposal. The sign: nobody names the better alternative.
The best-known documented misreading involves professional economists. At the 2005 American economics meetings, Paul Ferraro and Laura Taylor asked about 200 economists a textbook question. You have a free ticket to an Eric Clapton concert. The next-best option is a Bob Dylan concert, whose ticket costs $40 and which you value at $50. What is the opportunity cost of seeing Clapton: $0, $10, $40 or $50? The answer the authors expected was $10, the net value of the Dylan option. In Ferraro and Taylor's own results, only 43 of the 199 economists surveyed — 21.6% — chose that answer, fewer than the 25% a random guess across four options would produce.
122 min
Where the Opportunity Cost evidence is contested
The Ferraro and Taylor result is usually told as a story about economists. Other researchers read it as a problem with the question, or with the concept's definition.
The definition is not agreed. In a 2016 symposium in the Journal of Economic Education, Michael Parkin separated two versions. In the "quantity" version, the opportunity cost is the forgone thing itself, such as the Dylan concert. In the "value" version, it is what that thing is worth, which requires a further conversion into dollars. Daniel Arce, Rod O'Donnell and Daniel Stone replied that the value version is more useful in some settings, such as interest rates.
The Clapton question may be ambiguous. Potter and Sanders (2012), in the Southern Economic Journal, argued that any of the four answers can be defended. It depends on how the costs are counted.
The problem may be units, not the concept. In a 2014 Economics Bulletin paper, William Polley gave students the same problem in dollars only. They could keep a mystery box, or pay $40 for a box holding $50. Over 60% of students who got the mystery-box version answered correctly, compared with about 21% on the original wording.
Where this leaves a practitioner: the dispute is about definitions and wording, not about whether forgone alternatives matter. So name the alternative, then give its net value in dollars. That removes the step where the surveyed economists went wrong.
131 min
Opportunity Cost vs. nearby concepts
The confusion this audience makes most often is with sunk cost. The two point in opposite directions in time.
| Concept | What it measures | The deciding fact |
|---|---|---|
| Not in the library yetOpportunity cost | ||
| BusinessSunk cost | ||
| Not in the library yetAccounting (explicit) cost | ||
| BusinessCost-benefit analysis | ||
| BusinessComparative advantage |
A quick test: if the money or time can still be redirected, it carries an opportunity cost. If it is already gone, it is sunk.
142 min
Frequently asked questions about Opportunity Cost
What is opportunity cost in simple terms?
Opportunity cost is what you lose by not taking your best other option. Spend an evening on a side project instead of a paid shift, and the opportunity cost is the pay from that shift.
How do you calculate opportunity cost?
Take the benefit of the best alternative and subtract what that alternative would have cost you. If a rejected contract would pay $12,000 and need $2,000 of expenses, its opportunity cost is $10,000. Compare only the single best alternative, not all of them.
Is opportunity cost the same as sunk cost?
No. A sunk cost is already spent and cannot be recovered, so it should not affect the decision. An opportunity cost is a benefit you are about to give up, so it should always affect the decision.
Does opportunity cost apply to time as well as money?
Yes, and time is where it is most often missed. An hour spent in one meeting cannot be spent on anything else. Converting time to money, for example at a salary rate, lets you compare it with cash costs.
Is opportunity cost recorded in accounting?
No. Financial statements record explicit costs, money actually paid. Opportunity cost is an implicit cost. Economists subtract it to get economic profit, which can be negative even when accounting profit is positive.
Does opportunity cost still apply to startups?
Yes, and startups feel it more. A small team has few people and little runway, so each project displaces a larger share of everything else. A founder's own below-market salary is also an opportunity cost.
?6 questions
Questions people ask
What is opportunity cost in simple terms?
How do you calculate opportunity cost?
Is opportunity cost the same as sunk cost?
Does opportunity cost apply to time as well as money?
Is opportunity cost recorded in accounting?
Does opportunity cost still apply to startups?
§11 sources
Sources
Greenlaw, S. A., Shapiro, D., & MacDonald, D. (2022). Principles of Economics 3e, section 2.1. OpenStax.
Green, D. I. (1894). Pain-Cost and Opportunity-Cost. Quarterly Journal of Economics, 8(2), 218-229. quoted passage via Taylor, T. (2016), Dissecting the Concept of Opportunity Cost, Conversable Economist:
Friedrich von Wieser. Wikipedia.
Bharat, S. (2020). Opportunity cost: beginning, evolution and a much-needed clarification. BASE University Working Paper 02/2020.
Show all 11 sourcesShow fewer sources
Frederick, S., Novemsky, N., Wang, J., Dhar, R., & Nowlis, S. (2009). Opportunity Cost Neglect. Journal of Consumer Research, 36(4), 553-561.
College Board (2025). Trends in College Pricing: Highlights.
National Center for Education Statistics (2024). Annual Earnings by Educational Attainment.
Eisenhower, D. D. (1953, April 16). The Chance for Peace. The American Presidency Project.
NPR (2024, February 27). After 10 years of development, Apple abruptly cancels its electric car project.
Ferraro, P. J., & Taylor, L. O. (2005). Do Economists Recognize an Opportunity Cost When They See One? B.E. Journal of Economic Analysis & Policy, 4(1). full results table (43 of 199 respondents, 21.6%, chose the expected answer) reproduced in Polley (2014), entry 11 below.
Polley, W. (2014). Do students recognize an opportunity cost when they see one? Economics Bulletin, 34(3), 1550-1556.
