Good Debt, Bad Debt: A Useful Idea That Needs Sharper Edges
The classic distinction — borrow for assets, not consumption — is directionally right and dangerously incomplete. A better test: what the debt buys, what it costs, and what share of your income it commands.
Published · Loans & Debt · 1 min read
The folk taxonomy says mortgages and student loans are "good debt" (they buy appreciating assets or earning power) while card balances and financed vacations are "bad debt" (they buy the past). As a first pass, fine. As a decision rule, it has approved millions of terrible loans — because a category cannot bless a transaction. Plenty of mortgages have ruined households; plenty of card use is harmless float.
Where the taxonomy fails
- Good categories, bad instances. A degree with weak earning prospects financed at $180,000 is "student debt" and a bad purchase. A house at 45% of take-home pay is "mortgage debt" and a slow emergency. The label checked out; the numbers never did.
- Bad categories, good instances. A 0% promo on a needed appliance, paid on schedule, is "card debt" and costs nothing. A car loan is "consumption debt" that gets you to the job that pays everything else.
- The missing axis: size. The taxonomy says nothing about how much. Debt quality is partly a portfolio property — the same loan is fine at 10% of income and dangerous at 40%.
Three questions that actually sort debt
1. What does it buy? Something that appreciates, earns, or is genuinely necessary — versus something that will be gone before the payments are.
2. What does it cost? After-tax interest rate against realistic alternatives. Sub-5% secured debt and 27% revolving debt are different species regardless of what they bought.
3. What does it command? The payment as a share of income, stacked with everything else — the DTI lens, applied to your own comfort line rather than a lender's approval line.
A loan that passes all three is good debt for you; failing any one is a warning whatever the category. Price question two with the loan comparison tool and question three with the DTI calculator — the taxonomy becomes trustworthy once it has numbers under it.
Run your own numbers
More on loans & debt
- Credit Utilization: The 30% of Your Score You Control This Month
- Buy Now, Pay Later Is Still Debt — It Just Skips the Paperwork Feeling
- When You Must Borrow in an Emergency: Every Option, Ranked
This article is general education, not tax, legal, investment, or financial advice. Figures used in examples are illustrations, not quotes or predictions. For decisions that depend on your full situation, talk to a qualified professional.