Should You Pay Off Your Mortgage Early?

Two neighbors, same house, same loan, same rate. One sends an extra $250 a month with the payment and owns the house free and clear 6.7 years early. The other invests that $250 and retires with a larger portfolio. Both answers are defensible, and the gap between them is the decision.

Start with the math on the example loan: $400,000, 30 years, 6.7%, payment of $2,581 a month (Freddie Mac Primary Mortgage Market Survey, mid-2026). Add $100 a month and you save about $67,000 in interest and finish about 3.2 years early — 322 payments instead of 360. Add $250 a month and you save about $138,000 and finish about 6.7 years early — 280 payments. These are computed examples on this loan, not universal claims. The extra payment calculator runs your exact loan.

What extra payments actually do

Amortization front-loads interest. On this loan, the first payment is about $2,233 of interest and $348 of principal. An extra payment goes entirely to principal, which means it skips every dollar of future interest that principal would have carried. That is where the $67,000 and $138,000 come from.

The effect compounds over time. A payment made in year 2 is worth far more than the same payment in year 20, because it cuts interest across more remaining years.

The three numbers to compare

Computed on the example loan at 6.7%. The overpayment vs index investing calculator runs the comparison that matters next: what the same money earns in a diversified portfolio.

The case for paying it off

A mortgage payoff is a guaranteed return equal to your rate. In this example, that is 6.7% — risk-free, with no market exposure, and no tax on the savings. Very few investments offer a guaranteed 6.7%.

Payoff also changes cash flow. Once the loan is gone, the $2,581 payment becomes yours. For households near retirement, killing the largest fixed cost shrinks the gap that savings must cover each year.

There is also the year the payment disappears. Retirees with a paid-off house can often live on a fraction of the income their peers need, which is why the payoff question matters most in the decade before retirement. The guaranteed return compounds twice: once in avoided interest, once in a smaller retirement gap.

The case for investing instead

The counter-argument is liquidity. Home equity is trapped until you sell or borrow against it. A brokerage account is available the week you need it. If the money may be needed before the payoff date, investing keeps it reachable.

The tax angle cuts both ways. Mortgage interest is deductible only when you itemize — the payroll and tax tools show what itemizing actually requires. And investments sold in retirement are taxed as capital gains, which the capital gains guide explains in detail. Both facts belong in the comparison.

The behavioral half

The math assumes the invested dollars stay invested. In practice, portfolios get spent on cars, renovations, and market panic. If the extra money would not survive the decade intact, the mortgage is the better parking spot — the payoff cannot be undone at a bad moment.

The payoff date matters more than the payment

A lump sum changes the math the same way a monthly extra does, but the timing differs. A $10,000 principal payment in year 1 skips roughly 20 years of interest on those dollars; the same payment in year 25 skips almost none. Money applied early is worth multiples of money applied late.

Recasting is the middle option. With a lump sum, some lenders will recast the loan: the payment is recalculated on the smaller balance, the term stays the same, and monthly cash flow drops immediately. Recasting does not save interest the way prepayment does — the term is unchanged — but it frees monthly cash flow without selling anything. Ask your lender whether recasting is available and what it costs.

A decision rule that works

Four checks settle most cases:

1. The spread. If you can earn more than the mortgage rate after tax, investing wins on math. If the rate is higher, payoff wins. The spread is the whole debate. In this example, a long-run equity return near 8% beats 6.7% on paper — but paper assumes the market shows up on schedule, which it does not.
2. The buffer. Fund 6 months of expenses before any extra mortgage payment. A paid-off house does not pay for a job loss.
3. The source. Extra payments come from take-home pay. The take-home pay guide shows what a $250 monthly payment actually costs in after-tax dollars.
4. The temperament. If the mortgage keeps you awake at night, the guaranteed return is worth more to you than the market's best guess. That is a valid input, not a weakness.

The split-the-difference answer

Most households do not need a single answer. Paying half the extra toward the mortgage and half into investments buys the guaranteed return and keeps liquidity at the same time. It is the spreadsheet hedge: whichever side wins, the household loses less than a full bet on either.

Bottom line

Extra payments on this loan are a guaranteed 6.7% return, and that is a real number. The question is whether the same dollars earn more elsewhere, and whether you can afford to lock them away. Run the extra payment calculator and the investing comparison, and decide with both numbers in front of you.