Should You Pay Off Debt or Invest? (A Simple Framework)
This is one of the most common personal finance questions, and the math is actually straightforward once you know the framework. The answer comes down to one comparison: the interest rate on your debt versus the expected return on your investments.
The Core Rule
If your debt interest rate is higher than what you'd reasonably earn investing, pay off the debt. If the investment return is higher, invest. The stock market has historically returned about 8-10% per year on average over long periods.
Pay Off First (High Interest)
Credit card debt at 22% — pay this off immediately. Personal loans at 12-15% — pay these off. Any debt above 8% — prioritize paying this down. There's no investment that reliably returns 15-22% per year. Paying off high-interest debt is a guaranteed return at that rate.
Invest First (Low Interest)
Mortgage at 3-4% — invest instead. Student loans at 4-5% — likely better to invest. Car loan at 3-5% — invest, especially if you're getting an employer 401(k) match. When the debt rate is well below expected market returns, the math favors investing — your money grows faster in the market than the interest accumulates on the debt.
The Gray Zone (5-8%)
Auto loans at 6-7%, student loans at 6-8% — this is where it gets personal. The math slightly favors investing, but paying off debt provides guaranteed returns and psychological relief. A common approach: split your extra cash 50/50 between debt payoff and investing.
The Exception: Employer Match
If your employer matches 401(k) contributions, always contribute at least enough to get the full match before paying off any debt — even high-interest debt. A 50% or 100% employer match is an instant 50-100% return on your money. No debt payoff can beat that.
The Emotional Factor
Math says invest when rates are low. But being debt-free feels incredible and removes financial stress. If carrying a car loan at 5% keeps you up at night, paying it off might be the right move for you even if the spreadsheet says otherwise. Personal finance is personal — the best strategy is the one you'll actually follow.