"Good debt" and "bad debt" get thrown around constantly, usually as shorthand rather than a precise rule. The distinction is pointing at something real, but it is much leakier than the confident tone suggests, and treating it as a rule leads people to relax about debts that deserve attention.

The rough distinction

Debt commonly called good tends to share two traits: a relatively low interest rate, and a connection to something that holds value or raises your earning power. Mortgages and student loans are the standard examples. You borrow at a modest rate against a house that may appreciate, or a qualification that may raise lifetime income.

Debt commonly called bad carries a high rate and funds something that loses value immediately or builds toward nothing. Credit card balances on discretionary spending are the usual illustration, often 20% or more, against a purchase that is worth less the moment you own it.

Stated that way, the categories look obvious. In practice, almost every interesting case sits in between.

Where the labels break down

The distinction leaks in both directions, and the leaks matter more than the rule.

  • "Good" debt at the wrong size behaves badly. A mortgage at a comfortable rate is still a problem if the payment consumes most of your income. Nothing about the category protects you from taking on too much of it.
  • A student loan is a bet, not a guarantee. It raises earning potential on average. Borrowing a large sum for a qualification that does not lead to higher income leaves you with the debt and none of the benefit, a fact averages hide.
  • Rates move. "Low rate" is a property of a moment, not of a category. A variable-rate loan taken cheaply can become expensive without changing what it bought.
  • "Bad" debt is sometimes the sensible option. Putting an emergency car repair on a credit card when the alternative is losing your job is not a failure of discipline. It is the least-bad choice available.
  • 0% promotional periods invert things entirely. A balance costing nothing for eighteen months is not expensive today, but it may be after, and that is the part people forget to diarise.

The questions that do more work than the label

Rather than sorting debts into two bins, it is generally more useful to ask three things about each one you carry:

  • What rate is it charging? This determines what the debt actually costs you every month, and it is a fact, not a judgement. A balance at 24% is expensive whatever category it belongs to.
  • What did it buy, and does that still exist? Debt against an asset you still hold is a different situation from debt against a holiday two years ago: not morally, but practically, because one can be sold and the other cannot.
  • Can the payment survive a bad month? Debt that is comfortable at current income and catastrophic if that income pauses is worth knowing about in advance, regardless of its rate.

A simple version of the first question: multiply each balance by its annual rate and divide by twelve. That gives what each debt costs you per month in interest alone. A $4,000 balance at 22% is costing about $73 a month before you have reduced it by a cent; a $12,000 loan at 5% costs about $50. The smaller debt is the more expensive one, which is precisely the sort of thing the good/bad framing obscures.

Why the framing persists anyway

It survives because it encodes a genuinely useful instinct: borrowing to acquire something lasting is usually a better idea than borrowing to fund consumption, and cheap borrowing is better than expensive borrowing. As a rough prior, that is sound.

It becomes unhelpful when it is used to decide what to do next. "It is good debt" is not a reason to ignore a balance, and "it is bad debt" is not a reason to panic about a small one at a manageable rate. The rate and the balance tell you what to do; the label mostly tells you how the debt was described when it was sold to you.

If you are deciding which debt to put extra money toward, that ordering question has two well-known answers worth understanding, see our guide on the debt snowball versus the debt avalanche.

This is general information, not personal advice. Whether a specific debt makes sense for you depends on your rate, balance, income and wider situation, a financial advisor can help you weigh it properly.