What nobody tells you
- A mortgage on a house you can't actually afford is 'good debt' by category but dangerous in practice — the label doesn't override your specific numbers.
- Student loan debt for a degree with poor job market prospects can be some of the most dangerous debt that exists, precisely because it's marketed as automatically 'good.'
- Dangerous debt isn't only about the interest rate — it's also about whether the payment is manageable relative to your income if things go wrong.
The basics
- 'Good debt' generally describes low-rate, tax-advantaged, or appreciating-asset debt: mortgages, some student loans, business loans that fund real revenue growth.
- 'Dangerous debt' generally describes high-rate, consumption-based, or unsecured debt used for things that lose value immediately: credit cards, payday loans, most auto loans on cars beyond your means.
- The line isn't fixed — a mortgage stretched beyond your budget is dangerous, and a well-managed credit card paid in full monthly is neutral, not dangerous.
The framework
Four-question test
Run any debt through these four questions before deciding whether it belongs in the 'good' or 'dangerous' pile for your specific situation.
- 01
Does it finance something that grows in value or generates income, or does it finance something already consumed?
- 02
Is the interest rate low relative to realistic investment returns, or high enough to be actively working against you?
- 03
Is the required payment comfortably affordable if my income dropped by 20%?
- 04
Is there a clear payoff timeline, or could this balance persist indefinitely?
The playbook
The mistakes — what people get wrong
- Using the 'good debt' label to justify borrowing more for education or a home than you can realistically afford.
- Ignoring an auto loan where the car is worth less than the remaining balance (being 'underwater') — this quietly limits your options if you need to sell or trade in.
- Treating a 0% promotional rate as permanently safe without a plan for what happens when the promotional period ends.
Ask yourself
- Did this debt finance something that's growing in value, or something that's already gone?
- Could I still make this payment comfortably if my income dropped 20% tomorrow?
- Is there a clear date this debt will be paid off, or could it persist indefinitely?
Go deeper
- Practice
A debt classification list
Sort every debt into good, neutral, or dangerous using the four-question test above.
- Concept
Debt-to-income ratio
A useful stress-test number lenders use that you can apply to yourself.
- Book
Your Money or Your Life — Vicki Robin
Reframes debt and consumption in terms of life energy spent.
General educational information, not legal, tax, medical, or financial advice. Rules vary by country and change over time — verify with a qualified professional before acting.