Paying for something can make it difficult to walk away, even when continuing no longer makes sense. You may finish a bad movie because the ticket was expensive, keep an unused subscription because you have paid for it for years, or spend more money repairing an unreliable car.
A sunk cost is money, time, or effort already spent that cannot be recovered. Because that cost will remain the same whether you continue or stop, the better decision depends on recoverable value, future costs, future benefits, and your next-best alternative.
Checked July 17, 2026. This article explains a stable economic concept using educational materials from the Federal Reserve Bank of St. Louis.
What Is a Sunk Cost?
A sunk cost is a cost that has already occurred and cannot be recovered. The Federal Reserve Bank of St. Louis uses examples such as money already spent on research, consulting, repairs, or a movie ticket that cannot be refunded.
Sunk costs are not limited to money. They can also include time and effort that cannot be taken back. For example, the hours already spent reading a book are sunk once those hours have passed.
The important point is that a sunk cost does not change based on your next decision. An $18 nonrefundable movie ticket is gone whether you stay for the entire movie or leave after 30 minutes.
Sunk Cost and Sunk Cost Fallacy Are Different
The sunk cost is the unrecoverable resource itself. The sunk cost fallacy is the decision-making mistake of continuing mainly because of what has already been spent.
Common thoughts include:
- “I have already spent too much to quit.”
- “Stopping now would make everything I did a waste.”
- “I need to keep paying until I get my money back.”
These thoughts treat a past cost as though continuing could reverse it. In reality, continuing often creates new costs. The St. Louis Fed explains that putting more money or effort into an unsuccessful project is not logical merely because earlier spending cannot be recovered.
Everyday Sunk Cost Examples
The following comparison shows which part of each situation is already sunk and what should influence the next decision.
| Situation | Possible sunk cost | What matters now |
|---|---|---|
| Bad movie | Nonrefundable ticket price | How you want to use the remaining time |
| Unused subscription | Payments from previous months | Expected use and price of the next billing period |
| Exercise class | Nonrefundable amount already paid | Remaining benefits, travel time, and additional fees |
| Unreliable car | Past repair bills | Future repair costs, current resale value, and replacement costs |
| Business project | Unrecoverable development spending | Expected future revenue compared with additional costs |
Past spending can explain how you reached the current situation. It should not, by itself, determine whether another dollar or another hour should be committed.
Refunds and Resale Value Are Not Sunk
A cost is sunk only to the extent that it cannot be recovered. If you can receive a refund, cancel a pending payment, sell an item, or transfer a contract, the recoverable amount still matters.
For example, suppose you paid $300 for a course but can cancel today and receive $180 back. The entire $300 is not sunk. The $180 refund is part of the current decision because your choice can still affect whether you receive it.
The same principle applies to an investment or physical asset. The original purchase price may be in the past, but the amount you can receive by selling today is a current alternative. Transaction fees, cancellation penalties, taxes, and other costs may reduce the recoverable amount.
Sunk Cost vs. Opportunity Cost
Sunk cost looks backward. Opportunity cost looks at what you give up by making a choice now. The St. Louis Fed defines opportunity cost as the value of the next-best alternative when a decision is made.
| Question | Sunk cost | Opportunity cost |
|---|---|---|
| When does it arise? | Before the current decision | When choosing between current alternatives |
| Can the choice change it? | No | Yes |
| Should it guide the decision? | Generally no | Yes |
| Movie example | The nonrefundable ticket | The next-best use of the remaining time |
A person deciding whether to leave a bad movie should not focus on recovering the ticket price. The useful question is whether the remaining time would provide more value inside or outside the theater.
How to Decide Whether to Continue or Stop
Use the following process when past spending is making a decision difficult.
- Identify what is already gone. Separate unrecoverable money, time, and effort from costs that have not yet occurred.
- Calculate what can still be recovered. Include refunds, resale value, credits, and cancellation penalties.
- Estimate future costs. Count additional payments, time, maintenance, travel, and other resources required to continue.
- Estimate future benefits. Consider the usefulness, enjoyment, income, or other value you reasonably expect from continuing.
- Compare the next-best alternative. Ask what you could do with the same money and time if you stopped.
A practical test is to ask: “Knowing what I know today, would I choose to continue if I were making the decision for the first time?”
This question does not mean that every disappointing project should be abandoned. Continuing can still be reasonable when expected future benefits are greater than future costs. The reason for continuing, however, should be the value you expect from this point forward, not a desire to justify past spending.
The Bottom Line
A sunk cost is an unrecoverable cost from the past. The sunk cost fallacy occurs when that past cost causes you to continue an activity even though the expected future costs are greater than the expected future benefits.
Before deciding, separate what is permanently gone from what your choice can still change. Include available refunds or resale value, compare future benefits with future costs, and consider the opportunity cost of using your money and time elsewhere.