Should you pay off a 3% mortgage or invest?
With a 3% mortgage and a 7% expected investment return, investing the extra money ends roughly $179,268 ahead after 30 years. But that's only the math on averages — paying off a mortgage is a guaranteed return and buys real peace of mind.
Why the mortgage rate decides it
Paying off a mortgage is a guaranteed return equal to the mortgage rate. Investing is an expected return with risk. So the comparison is simply 3% guaranteed vs ~7% (risky) expected:
- When the mortgage rate is well below your expected return (like 3% vs 7%), investing usually wins on average — your money compounds faster than the loan costs.
- When the mortgage rate approaches or exceeds your expected return, paying it off wins — and it's a certain win, with no market risk.
- Guaranteed vs risky matters. A paid-off house lowers your fixed costs and sequence-of-returns risk in retirement. Many people rationally choose the guaranteed return even when investing edges it out on paper.
Before you decide
A few things this comparison assumes you've already handled: capturing your full 401(k) match (an instant ~100% return that beats both), paying off any high-interest debt (credit cards dwarf a mortgage rate), and keeping an emergency fund. Money locked in home equity is hard to access without a sale or a HELOC — so don't pay down the mortgage with money you might need.
Assumptions: $450k home, 20% down, 30-yr term, an extra $12,000/yr toward principal, 7% investment return, 3% inflation, single filer. Mortgage interest is only deductible if you itemize — most people take the standard deduction, so this treats it as non-deductible. Model your own numbers in the calculator.
The return is small, but it is certain
Every dollar of extra principal buys a guaranteed, risk-free return equal to your mortgage rate. Investing instead offers a higher expected return, but an uncertain one. At a modest fixed rate the paper math tilts toward investing — yet the case for paying the loan down was never only about the paper math.
A shrinking mortgage balance pays off in every market, including the ones where stocks fall for years. That certainty has real value to the person holding it. Someone who would lose sleep in a downturn — or worse, sell in a panic and lock in the loss — may well come out ahead accepting the smaller sure thing.
This is a genuinely personal call, not a math error. Trading a slightly higher expected return for a guaranteed one is a rational preference, provided the match is captured, high-interest debt is gone, and an emergency fund is in place first. Know how you actually behave when markets drop, and weight the decision accordingly.
Common questions
Should I pay off a 3% mortgage or invest?
On average, investing wins by about $179,268 over 30 years because a 7% expected return beats the 3% guaranteed by paying it off. But paying off is guaranteed and risk-free, which many people rationally prefer.
Is it worth paying off my mortgage early?
Financially it's worth it when your mortgage rate is at or above your expected after-tax investment return. Below that, investing usually builds more wealth — though a paid-off home reduces risk and fixed costs, which has real value beyond the math.
What should I do before paying extra on my mortgage?
Capture your full 401(k) match, clear high-interest debt (credit cards), and hold an emergency fund first — each of those beats extra mortgage payments. Only then does paying down a low-rate mortgage compete with investing.