What's that habit really costing you?
Any recurring spend — or several combined — turned into what it's worth invested instead, how many work-hours it costs you, and how much sooner you could reach FIRE without it.
Opportunity Cost Calculator
Invested value: your recurring spend, converted to a monthly amount, compounded monthly at your entered return rate.
When multiple categories are active, all figures — invested value, FIRE impact, and work-hours — reflect the combined total monthly amount across every selected category.
FIRE impact estimate: this is a simplified illustration, not your personal plan. We assume a $1,250,000 FIRE target (25× a $50,000/year expense baseline) and a representative saver already investing $1,250/month. We compare how long that saver takes to reach $1,250,000 with vs. without this habit's amount added to their monthly investing. The difference is the estimated delay.
- Does not use your actual income, expenses, or savings rate
- Does not account for inflation or taxes
- For a FIRE date based on your real numbers, use RetireSmart
Work-hours equivalent: annual spend on this habit ÷ your hourly wage (pre-tax, not adjusted for benefits).
Frequently asked questions
Opportunity cost is what you give up by choosing one use of money over another. If you spend $6 a day on coffee instead of investing it, the opportunity cost isn't just the $6 — it's what that $6 could have grown into if invested instead.
The math behind it is real — small recurring expenses do add up and compound significantly over decades. But it's often oversold as the main lever for building wealth; income growth and overall savings rate usually matter more. Think of this calculator as a helpful gut-check, not a strict rule.
At a 7% annual return, investing $6/day instead of spending it grows to roughly $220,000 over 30 years — even though the actual cash spent over that time is far less. Try it above with your own numbers, or select multiple category chips to see the combined impact of several habits at once.
It can help, but the effect is usually smaller than people expect unless the habit is a larger recurring cost (like a car payment). The FIRE-impact estimate above is a rough illustration — your actual timeline depends far more on your income, total savings rate, and investment returns. Use RetireSmart for a number based on your real situation.
7% is a commonly used estimate for average long-term stock market returns (nominal — this calculator doesn't adjust for inflation). Real returns vary considerably year to year, so try a range, like 4–10%, to see how sensitive the outcome is to your assumption.
No. This tool assumes a constant return rate and doesn't adjust for inflation, taxes on investment gains, or changes in the cost of the habit itself over time. It's meant as a quick, directional estimate — not a personalized financial plan.
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This calculator shows the general cost of a habit. RetireSmart models your actual income, spending, and investments to show exactly when you can stop working.