Should You Pay Off Your Mortgage Early or Invest the Difference?

In October 2022, the average 30-year fixed mortgage in the United States hit 7.08%. Twenty months earlier, in January 2021, it had bottomed at 2.65%. Same instrument, same country, same Federal Reserve. The cost of borrowing money to buy a house had nearly tripled in under two years.

That number broke people. Not the ones who were buying. The ones who already owned. They looked at their neighbors stuck at 7%, looked down at their own mortgage statement at 3%, and started wondering if they should pay the thing off anyway. Just to be done with it. Just to feel like they owned something.

I get a version of that question every month.

It's reliably misunderstood, and the misunderstanding runs both ways. The math people will tell you to never pay extra on a 3% mortgage because the market returns more. The Dave Ramsey people will tell you to pay it off as fast as humanly possible because debt is bondage. Both are confidently wrong about half the time. The real answer depends on a single number on your mortgage statement and one honest assessment of yourself.

The rule first, then the reasoning.

If your mortgage rate is above 6.5%, pay it down aggressively, once you've captured your employer 401(k) match and kept an emergency fund intact. If it's below, invest the difference. 6.5% is my line. It's defensible by the data, and it's also a judgment call. The number on your statement does most of the work in this decision. Find it.

I have a mortgage. I have built spreadsheets that proved I should pay it off. I have built different spreadsheets the same week that proved I shouldn't. The fact that I'm a CFP and a CPA has not, as far as I can tell, immunized me from the human urge to be done with debt. The math is the math. The wanting is something else.

A mortgage paydown returns one specific thing: exactly your interest rate, every year, until the loan is gone. There is no maybe in that number. There is no thirty-year average that might or might not show up. You pay $1,000 against a 6% mortgage, and you have saved $60 a year in interest for as long as that $1,000 would have otherwise been borrowed. The check clears. The interest doesn't accrue.

A stock portfolio returns the long-run equity premium, on average, eventually, with volatility that bears no resemblance to a straight line. The 10% historical figure you've seen quoted smooths over the 2000–2009 lost decade, the 2008 collapse, the 2022 drawdown that punished stocks and bonds in the same calendar year, and a hundred other stretches that felt like anything but 10% while you were living through them. The case for investing instead of paying down debt assumes you'll stay invested through all of those stretches without flinching. Most people flinch.

Above 6.5%, the certain thing beats the uncertain thing on a risk-adjusted basis. Below it, the spread is wide enough to justify staying invested, provided you can ride out a 30% drawdown without selling. Any spreadsheet calculation becomes useless if you can’t hold during the drawdown,

The 6.5% threshold is a nominal comparison. Itemizers pay an effective mortgage rate lower than what their statement shows. Taxable investors earn an effective return lower than what the index publishes. Both sides get adjusted by the tax code, and for high earners in high-tax states, the adjustments are not small.

Start with itemization, because that's the gate. For 2026, the standard deduction for a married couple filing jointly is $32,200. Total itemized deductions have to clear that figure before any of them produces a tax benefit. The arithmetic that gets you there changed in 2025. OBBBA raised the SALT cap to $40,400 for joint filers in 2026, up from the $10,000 cap that ran from 2018 through 2024. The benefit phases down at a 30% rate for households with modified AGI above $500,000, snaps back to $10,000 once MAGI hits $600,000, and reverts to $10,000 for everyone in 2030.

For a Westchester or New Jersey couple at $300,000 to $500,000 of MAGI, this changes the math. State income tax, property tax, mortgage interest, and charitable giving will now clear $32,200 in most cases, which means each dollar of mortgage interest produces a marginal tax benefit at the household's combined marginal rate. For an Ohio couple at the same income, probably not. For a Manhattan partner at $1M of MAGI, the SALT cap is back to $10,000 and the deduction is partial again. The mortgage interest deduction is real for some households and phantom for others, depending on AGI and zip code.

When it is real, the formula is the one you'd expect:

After-tax mortgage rate = nominal rate × (1 − marginal tax rate)

The investment side gets the same treatment. The 10% historical equity figure is pre-tax. A taxable brokerage account pays tax on dividends along the way and on capital gains at sale. For a high earner, that means 15% or 20% federal long-term capital gains, plus 3.8% net investment income tax above the threshold, plus state tax. The realized after-tax return on a broad index fund held in taxable for someone in the top brackets lands closer to 7-8% than 10%. A Roth IRA preserves the full pre-tax return. A traditional 401(k) defers the tax and pays ordinary rates on the back end, which is usually still favorable if the retirement bracket is lower than the contribution bracket.

The honest comparison, for a household at a 40% combined federal-and-state marginal rate that itemizes (Westchester, much of NJ and CT, parts of California):

The spread still favors investing below the threshold. It narrows above it. The 6.5% nominal line translates to something closer to 6% in after-tax terms for itemizing households in high-tax states, because the after-tax mortgage rate falls faster than the after-tax equity return does. For households that don't itemize, the line stays at 6.5%.

This is a small adjustment to a number that was already a judgment call. Worth knowing it exists. Not worth pretending the spreadsheet has finally answered the question.

The mortgage-versus-investing debate gets fought in a vacuum. Most of the time, the right answer is neither. The dollar you're trying to allocate should be going somewhere else entirely, and you haven't gotten there yet.

The order isn't complicated. Most people just haven't bothered to write it down.

Capture your employer 401(k) match in full. A 50% or 100% instant return is unavailable anywhere else on planet Earth, and walking past it is the most expensive mistake in personal finance. It's also the most common. There are otherwise sophisticated people who will spend an hour comparing index funds and then leave a 100% match on the table because they want to keep their take-home pay up. I don't have words for this.

Eliminate any debt above 6.5%. In practice that means credit cards, personal loans, and any private student debt that wasn't refinanced when rates were generationally low. A 22% APR is not a negotiating partner. You don't reason with it. You kill it.

Fund an HSA if you have a qualifying high-deductible health plan. The triple tax treatment (deductible going in, tax-free growth, tax-free withdrawals for qualified medical expenses) makes it the most efficient account in the tax code. The right move is to pay current medical bills out of cash flow and let the HSA balance compound for thirty years. Most people treat their HSA as a checking account for copays and miss what it is.

Fill the remaining tax-advantaged space. Max your 401(k) beyond the match toward the 2026 employee deferral limit of $24,500. Fund a Roth IRA directly if you're under the income limits, or through the backdoor if you're above them. The 2026 IRA contribution limit is $7,500, or $8,600 if you're 50 or older. After that, a taxable brokerage account holds whatever's left, indexed broadly, held long enough for the long-term capital gains rate.

Alternatives like real estate and private equity belong on this list only if you understand what you own. Most retail investors don't, and most of the products marketed to them are worse than a broad index fund.

The mortgage, if it's below 6.5%, comes last. Everything above it returns more for less effort.

The mortgage rarely deserves the airtime it gets. Find your rate. Run the after-tax math. Then look at the rest of the waterfall and figure out which step you're actually standing on.

Picture your money flowing down a series of ledges, each one capturing everything it can before the overflow spills to the next level. Financial priorities work the same way.

Step 1: Employer Match on Your 401(k)/403(b) 

If your employer matches contributions and you're not capturing every dollar of that match, you are declining free money. A 100% immediate return beats everything else on this list. Contribute enough to get the full match before doing anything else.

Step 2: High-Interest Debt 

Credit cards, personal loans, anything above 6.5%. These get paid off with the same ruthlessness you'd apply to a house fire. You don't negotiate with a 22% APR. The guaranteed return from eliminating high-interest debt beats any expected market return on a risk-adjusted basis.

Step 3: HSA (If You're Eligible) 

The Health Savings Account is the most tax-efficient account in existence. Contributions are pre-tax, growth is tax-free, and qualified withdrawals are tax-free. Triple tax benefit. Max it before anything else.

Step 4: Max Your Retirement Plan 

Your 401(k) beyond the match, 403(b), whatever your employer offers. Tax-deferred growth compounds quietly and ruthlessly over decades. Let it.

Step 5: Backdoor Roth IRA

Tax diversification is the goal here. You want money in both pre-tax and post-tax buckets so future-you has flexibility when tax rates (and your income) are unknowns.

Step 6: Taxable Brokerage Account 

No contribution limits, no restrictions. Low-cost index funds, held long enough to benefit from favorable capital gains rates. This is where real wealth accumulates once you've maxed every tax-advantaged vehicle.

Step 7: Alternative

Real estate, private equity, and other asset classes are optional for most people, but definitely worthwhile for those who understand what they're buying and why.

Step 8: Low-Interest Debt (Including Your Mortgage)

Debt below 6.5% sits at the bottom of the waterfall. Mathematically, your money works harder almost anywhere else first.

Here's where the certified financial planners earn their keep, and where the internet math-bros go wrong.

Stress has a dollar value.

I've watched people with objectively optimal portfolios make catastrophic panic decisions in market downturns selling everything at the bottom or abandoning a decade of gains in a week of fear all because they were carrying more risk than their nervous system could actually tolerate. The theoretical 7-point spread between their mortgage rate and the market's expected return evaporated the moment the VIX spiked and their hands started shaking over the sell button.

A paid-off house changes behavior. It changes decision-making. It creates a psychological floor below which your financial life cannot fall, and that floor has value that doesn't show up in any spreadsheet.

If carrying a mortgage (even a mathematically favorable one) means you'll panic-sell your investments during the next correction, then your effective market return isn't 10%. It's whatever return you lock in when fear makes the decision for you. That number is usually ugly.

The question worth asking yourself, and answering honestly: Have I sold investments during a downturn before? If the answer is yes, factor your own behavior into the calculation. Behavioral drag is real, it's measurable, and it destroys more wealth than almost any other single factor.

You don't have to choose.

Split the extra cash by putting half toward your mortgage principal and half into a brokerage account or maxing tax-advantaged vehicles. You sacrifice a little mathematical purity for a lot of psychological durability. Your mortgage balance drops. Your portfolio grows. You sleep better than the pure-invest crowd, and you accumulate more than the pay-it-off-first crowd. The middle path is underrated in finance, where everyone wants a definitive answer.

Life is not a finance textbook, and neither is your mortgage.

If you are within ten years of retirement, the calculus changes sharply regardless of your rate.

Entering retirement with a mortgage payment is a sequence-of-returns risk multiplier. If the market drops 35% in year two of your retirement while you're still writing a mortgage check every month, you're selling assets at the worst possible time just to service debt. That combination (forced selling plus a bad market) can derail even a well-funded retirement.

Carrying a paid-off home into retirement means your fixed costs are dramatically lower, your portfolio needs to produce less income, and a bad market year is painful but survivable. With a mortgage, the same bad year might require withdrawals that permanently impair your portfolio's ability to recover.

Proximity to retirement is the variable that overrides the interest rate argument.

Pull up your mortgage statement, and find the interest rate.

The mortgage-versus-investing question sounds like a math problem. It's actually a self-knowledge problem wearing a math problem's clothing.

Figure out who you are. Then run the numbers.