Calculators / The Matching Rule
The Matching Rule
"If I had to invest the same amount I'm about to spend, would I still buy?"
If you want a $400 gadget, you should treat it as if it costs $800, with $400 going to the merchant and another $400 invested for your future self.
— Debugging Your Personal Finance, Chapter 13
True cost (purchase + matched investment): —
What the matched $X grows to in the horizon: —
—
Nick Maggiulli's rule (via Ch. 13): if you want a $X non-essential item, force yourself to invest $X in income-producing assets at the same time. The "true cost" doubles, and if the math still makes sense, the purchase is genuinely worth it.
From Chapter 13 of Debugging Your Personal Finance. Simple calculator · Inputs stay in your browser · Not financial advice.
A simplified calculator for education, not financial advice. See the disclaimer.