Debt-Freedom Opportunity Cost Calculator
Example: Current balance: 15000 $ · Debt APR: 19.99 % · Payoff term: 48 months · Expected investment return (annualized): 8 %/yr · Years to invest after payoff: 15 years
| Investment portfolio value after payoff period | $157,923 |
| Total interest paid on this debt | $6,906 |
| Monthly payment that gets redirected to investing | $456 |
| Wealth unlocked by reaching zero | $157,923 |
Worked example
A $15,000 balance at 19.99% APR paid off over 48 months costs about $6,500 in interest and requires a monthly payment of roughly $454. Once the debt is gone, investing that same $454/month at an 8% annual return for 15 years grows to approximately $157,000. The debt did not just cost $6,500 in interest — it cost access to the wealth-building power of those dollars during the payoff years and the compounding years that follow.
Frequently asked questions
Should I pay off debt or invest simultaneously?
Mathematically, the decision hinges on rates: if your debt APR exceeds your expected investment return, paying off debt first wins on pure math. At 19.99% APR versus an 8% expected return, debt payoff wins by a wide margin. Many people choose to do both — contribute enough to capture any employer 401(k) match (guaranteed 50–100% return) while paying down high-rate debt aggressively.
Is an 8% investment return a realistic assumption?
The S&P 500 has averaged roughly 10% nominal annual returns over long periods (Source: Federal Reserve). After inflation (roughly 2–3%), the real return is closer to 7–8%. No year is average — returns vary widely — but over 15+ year horizons, a diversified equity portfolio has historically produced returns in this range.
What does 'opportunity cost' mean in this context?
Opportunity cost is what you give up by choosing one path over another. When you carry high-rate debt, every dollar servicing interest is a dollar that cannot compound in a brokerage account. This calculator makes that abstract concept concrete: the opportunity cost of this $15,000 balance is not $6,500 — it is $157,000 of future wealth.
Does this apply to student loans or mortgages at lower rates?
Yes, but the calculus shifts. At 4–5% APR (near or below expected investment returns), the opportunity cost of aggressive extra payments shrinks dramatically. At those rates, many financial planners recommend investing the difference rather than prepaying, especially if the interest is tax-deductible.