Opportunity Cost.

Opportunity cost is the value of the best thing you give up when you choose one option over another, whether or not money changes hands.

Reviewed by Joseph Citizen, Founder · Last reviewed July 12, 2026

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Opportunity Cost

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In plain English

Opportunity cost is what you sacrifice by picking one use of your money, time, or attention instead of the next-best alternative. Every choice has one, even when nothing is spent: money sitting in cash has the opportunity cost of the return it could have earned invested. It is one of the most useful ideas in finance because it reframes decisions around what you trade away, not just what you pay. The real cost of a purchase is not only its price but the growth that money could have produced elsewhere.

Most useful ages

18 to 70

001The Real Cost

You spend 5,000 dollars on a vacation. The opportunity cost is not just the 5,000; it is what that money could have become invested, perhaps around 25,000 dollars over 30 years at 7 percent.

01Why it matters

Thinking in opportunity cost turns everyday choices into clearer tradeoffs, especially the long-run cost of spending money that could have compounded instead.

02The math, step by step

You spend 5,000 dollars on a vacation. The opportunity cost is not just the 5,000; it is what that money could have become invested, perhaps around 25,000 dollars over 30 years at 7 percent.