Lifestyle
How rich would I be if…
Take any fixed monthly expense and imagine investing it instead. Compounded over the years, the counterfactual number is often startling.
A car payment, the extra rent for a bigger place, a daily lunch out, each is a fixed sum leaving your account every month. Redirect it into investments and it compounds. This shows the counterfactual: what you'd have if you had invested a recurring expense instead of spending it. Not a regret, a lens on what fixed costs really cost.
Pick an expense and how long you'd have invested it.
Worked example
A $500 monthly car payment, invested at 7% for 30 years instead:
| Measure | Value |
|---|---|
| Total contributed | $180,000 |
| Growth on top | $429,985 |
| What you'd have after 30 years | $609,985 |
$500 a month is $180,000 contributed over 30 years. But invested it becomes $609,985, because $429,985 of it is compound growth. That's the case for keeping fixed monthly costs low: each one is a claim on a much larger future number.
Questions
Is this telling me not to buy a car?
No, you need to get around, and some expenses are worth it. It's a way to compare the true long-run cost of a recurring expense against its benefit, so a $500 car payment is a choice you make with eyes open, not by default.
Why is the growth bigger than what I put in?
Because compounding runs for decades. Over 30 years at 7%, money roughly doubles more than three times, so the growth on early contributions dwarfs the contributions themselves. The longer the horizon, the more lopsided it gets.
Related tools
- Coffee habit the small-daily version
- Cost of waiting to invest why the head start matters
- FIRE calculator where redirected money leads
A counterfactual thought experiment on a steady assumed return, not a forecast or advice. Not financial advice.