Comparison explorer
Pay down the mortgage, or invest?
A guaranteed saving against an expected return. Move your rate and term to see how the total dollars change — and where the two sides become too close to separate.
The shaded band is our expected investment return after costs: 3.6% to 8.6% a year. Inside it, the two sides are close. There is no single crossover rate.
At 6%, this sits inside the range — it is genuinely close
The guaranteed saving of 6% falls between 3.6% and 8.6%, which is where our expected investment return lands after costs. Nothing in the arithmetic separates them, so the tiebreakers are the ones below: certainty, liquidity, and how you would behave in a bad year.
- Money used to pay debt is hard to get back. Money in a brokerage stays available — worth something when the comparison is close.
- Paying down a mortgage converts liquid money into home equity, which you can generally only reach by selling or borrowing again.
- A paid-down mortgage does not lower the monthly payment until it is gone or recast — it shortens the term instead.
Prepaying $10,000
$32,919
interest avoided over 25 years at 6% — guaranteed.
Investing the same amount
$39,423
growth at the middle of our expected range over the same period — an estimate, not a promise.
Prepaying $10,000 with 25 years left avoids roughly $32,919 of interest. The rate you earn is the same 6% whatever stage of the loan you are at — a shorter remaining term simply means fewer years for that saving to accumulate, so the total is smaller.
Extra mortgage payments avoid interest at your note rate, with certainty. That is a genuinely good return when the rate is high and a mediocre one when it is not — which is why the same person can reasonably prepay a 7% loan and invest alongside a 3% one.
The stage of the loan does not change the rate you earn by prepaying. It changes how long the saving has to accumulate: prepaying with five years left avoids far fewer dollars than the same prepayment with twenty-five years left, at exactly the same percentage.
We deliberately do not estimate a tax benefit for you. Mortgage interest helps only if you itemize, and only above the standard deduction — for most households the incremental benefit is zero. If you have worked out your own effective after-tax rate, enter it below and the comparison will use it.
This is one decision. See the whole picture.
The same engine runs a short guided journey that puts this decision in order against everything else competing for the money.
Common questions
Where these figures come from
2026 figures · checked 2026-08-18- IRSIRS — Publication 936, home mortgage interest deductionWhich mortgage interest is deductible, and the qualifying-debt limits
- Federal ReserveFederal Reserve — H.15 selected interest ratesPrime rate and other reference rates used in the explorers
Statutory limits are taken from these publications. Economic assumptions — expected returns, emergency-fund targets — are ours, are shown wherever they are used, and are not sourced from anyone.
We'll tell you when this decision moves
Rates and tax rules are what tip the balance between paying down a loan and investing. One email a month, only when something actually changed.
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