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.
What you'd invest
If you'd invested it instead
Pick an expense and how long you'd have invested it, then press Calculate.
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 a fixed monthly cost costs once compounding is counted.
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.