Should I Pay Off My Mortgage or Invest?
Paying down the mortgage is a guaranteed, after-tax return equal to your rate. Investing is an uncertain one. Compare them on the same basis.
Key takeaways
- An extra principal dollar earns a risk-free return equal to your mortgage rate.
- If you do not itemize, that return is already after tax — which makes it stronger than it looks.
- Investing must clear your mortgage rate after tax, not before, to win.
- Home equity is illiquid; investments are not. That difference has value beyond the arithmetic.
- Sequence of returns matters: the same average return can produce different outcomes depending on when losses occur.
Short answer: compare your mortgage rate with your expected *after-tax* investment return, then adjust for liquidity and certainty. At a 6.6% mortgage rate with no itemized deduction, investing has to clear 6.6% after tax to win — a higher bar than most quick comparisons assume.
Why extra principal earns exactly your rate
A dollar of extra principal removes all future interest that dollar would have accrued. The return is precisely the note rate, it is guaranteed, and it is not taxed. There is no sequence risk and no volatility. Very few investments offer that combination.
When the deduction changes the answer
If you itemize and your mortgage interest genuinely exceeds the standard deduction, your effective borrowing cost is lower than the note rate, which lowers the bar for investing. If you take the standard deduction — the more common case — the note rate is your true cost. Work this out before assuming a tax break exists.
| Situation | Leans toward |
|---|---|
| High mortgage rate, taxable investing only | Paying down the mortgage |
| Low legacy rate, employer match available | Investing |
| Thin emergency reserves | Liquidity first, then decide |
| High-interest consumer debt outstanding | Neither — pay that first |
| Retirement accounts not maxed | Investing, for the tax shelter |
Order of operations
- Build a cash reserve that covers your full housing cost for several months.
- Capture any employer retirement match — an immediate return nothing else matches.
- Clear debt priced above your mortgage rate.
- Then compare extra principal against additional after-tax investing.
The psychological return is real
A paid-off house lowers your required income permanently. If a smaller fixed obligation lets you take career risk, retire earlier or sleep better, that is a legitimate reason to accept a slightly lower expected return. Optimization is not only arithmetic.
Frequently asked questions
- Is it better to make extra payments monthly or in one lump sum?
- Earlier is better because interest accrues on the balance. A lump sum today saves more than the same amount spread over a year, though monthly extra payments are easier to sustain.
- Should I recast after a large principal payment?
- A recast lowers the required payment without changing the rate or term end date, for a small fee. It helps cash flow but does not reduce interest beyond what the principal payment already did.
- What return should I assume for investments?
- Use an after-tax figure you would be comfortable defending, and test the decision at a lower one. If the answer flips between reasonable assumptions, the two options are close enough that liquidity should decide.
Sources
- Consumer Financial Protection Bureau: Paying off your mortgage early — accessed 2026-07-28
- Internal Revenue Service: Publication 936, Home Mortgage Interest Deduction — accessed 2026-07-28
Educational content only. This is not a loan offer, and your actual terms depend on your lender, credit profile and property.
Investment returns are uncertain and are modelled here as assumptions, not predictions. This is not investment advice.