Opportunity Cost Calculator

Opportunity Cost Formula

Opportunity Cost = Return of Best Alternative − Return of Chosen Option

For investment decisions over time:

Opportunity Cost ($) = Future Value of Alternative − Future Value of Chosen Path

Both values are calculated over the same time period using the appropriate compounding method.

Compounding Methods

Simple Interest: FV = Principal × (1 + Rate × Years)

Annual Compound Interest: FV = Principal × (1 + Rate)^Years

Monthly Compound Interest: FV = Principal × (1 + Rate/12)^(Years × 12)

The Core Concept: Implicit Cost

Economists distinguish between two types of costs:

• Explicit costs — actual cash payments (rent, wages, materials)
• Implicit costs — the value of resources used that have no direct cash payment

Opportunity cost is an implicit cost. It’s never shown on a profit-and-loss statement, but it’s real.

Economic Profit = Accounting Profit − Opportunity Cost

A business can be “profitable” in accounting terms but economically unprofitable if the owner’s time and capital could earn more elsewhere.

Real-World Examples

Buying a house vs. renting and investing the down payment: A $100,000 down payment used to buy a home cannot also be invested in the stock market. If the home appreciates 3% annually but the stock market returns 9% annually, the 10-year opportunity cost is enormous.

Taking a job vs. staying in school: If you earn $50,000/year by working, but a graduate degree would boost your earnings to $80,000/year after 2 years of school costs, the opportunity cost of working is the forgone higher salary over your career.

Leaving money in a savings account earning 0.5%: When a high-yield savings account or CD pays 5%, the opportunity cost of keeping money in a low-rate account is significant.

Worked Example

James invests $50,000 in a rental property that earns 4% annually. His best alternative was an index fund returning 9% annually. Time horizon: 10 years. Annual compounding.

• Chosen (rental): $50,000 × (1.04)^10 = $74,012
• Alternative (index fund): $50,000 × (1.09)^10 = $118,368
• Opportunity Cost = $118,368 − $74,012 = $44,356

That $44,356 represents the price James paid for choosing the rental over the index fund.

Pro Tips

• Opportunity cost applies to time, too. Every hour spent on one task is an hour not available for another.
• In business strategy, entering one market means not entering another. Always consider what you’re giving up.
• Sunk costs are NOT opportunity costs. Past spending that cannot be recovered should not influence future decisions.