Pay Off Debt vs. Invest
Compare the debt's after-tax interest rate against your expected after-tax investment return. Credit cards (20%+) always lose to investing. Mortgages (5-7%) are usually close to a tie. Always get the 401(k) match first regardless.
The short answer
Match the employer contribution first, clear anything above about 8%, then invest.
The comparison is between a guaranteed return and an expected one. Paying off a debt returns its interest rate with certainty; investing returns a long-run average with considerable variance around it.
That asymmetry is why the answer is not simply "invest when the expected return is higher". A guaranteed 8% is worth more than an uncertain 10%, because you can spend the first one and only hope for the second.
Above roughly 8% the debt wins on any reasonable view. Below about 5% investing usually wins. Between the two it is genuinely close, and the tie-breaker is how much the debt weighs on you.
Where each dollar should go
In order. Do not move down the list until the step above is satisfied.
| Employer match | Always first | An instant 50% or 100% return. Nothing else competes. |
|---|---|---|
| Debt above 8% | Pay it off | A guaranteed return at that rate beats an uncertain market return. |
| Small emergency fund | Build it | Without one, the next surprise goes back on the card you just cleared. |
| Debt at 5% to 8% | Genuinely close | Split it, or resolve it on how much the debt bothers you. |
| Debt below 5% | Pay the minimum | Invest the rest; the expected return comfortably exceeds the cost. |
The order matters more than the arithmetic. Skipping the employer match to overpay a 6% mortgage is the most expensive version of this decision.
Where people go wrong
- Overpaying a low-rate mortgage before capturing the full employer match.
- Comparing a guaranteed debt payoff against an expected market return as though they carried the same certainty.
- Assuming mortgage interest is deductible. Most households take the standard deduction, so it is not.
- Clearing cards with no emergency fund, then reborrowing on them at the first surprise.
Common questions
Should I pay off my mortgage early or invest?
At typical mortgage rates the expected market return is higher, so investing usually wins on arithmetic. The counter-argument is real: a paid-off house is a guaranteed return and a fixed cost removed from your life. If a mortgage genuinely troubles you, clearing it is a defensible choice even when the spreadsheet disagrees.
What about student loans?
Federal loans carry protections — income-driven repayment, forgiveness programmes, deferment — that private loans do not, and those have value beyond the rate. Aggressively prepaying a federal loan can forfeit them. Clear private loans on the same rate test as any other debt.
Does the debt snowball beat the avalanche?
Mathematically the avalanche — highest rate first — always costs less. The snowball, smallest balance first, wins on follow-through for many people, and a plan you finish beats an optimal one you abandon. The difference in interest is usually small enough that this is a fair trade.
| Pay Off Debt | Invest | |
|---|---|---|
| Get 401(k) employer match | Always first | Always first |
| Build $1K emergency fund | Always first | Always first |
| Credit card debt (20%+) | PAY OFF — no investment beats this | — |
| Personal loan (12-15%) | Pay off | — |
| Auto loan (6-8%) | Pay extra if other goals met | Invest if return expectation > rate |
| Student loan (federal, 5-7%) | Pay minimums, invest extra | Long-term investing usually wins |
| Mortgage (5-7%) | Pay minimum | Invest extra — expected return usually exceeds the rate |
| Investment "rate" | Guaranteed (interest saved) | Average ~10% nominal, ~7% real, NOT guaranteed |
Choose Pay Off Debt if
- Debt rate is above 10% (after tax deduction if applicable).
- You're late on payments or underwater on payment-to-income ratio.
- You sleep poorly knowing you have debt.
- You can't qualify for new credit because of high utilization.
Choose Invest if
- All non-mortgage debt is at or below ~7%.
- You have a 6-month emergency fund.
- You're maxing tax-advantaged accounts first (401k, IRA, HSA).
- You'll stay invested through inevitable downturns.
Run the numbers yourself
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