Guide · 7 min read
When a Refinance Pays for Itself
A refinance is not a rate decision, it is a time decision: how long will you actually keep this loan? The break-even month is the answer to everything.
On a $400,000 loan, dropping 7.5% to 6.0% saves $399 a month. With $6,000 in costs, the refinance breaks even in 1 yr 4 mo — and nets $137,516 if held for the full 30-year term.
The arithmetic is one division. On a $400,000 balance, the payment at 7.5% is $2,797 and at 6.0% it is $2,398 — a saving of $399 a month. Closing costs of $6,000 divided by $399 is fifteen months, so the refinance starts paying in year two of the new loan, around February 2028 in this example.
Everything else is commentary on that division. A bigger rate drop shortens the break-even. Lower costs shorten it too. Planning to move before the break-even month makes the refinance a loss dressed as an improvement.
The short-term trap and the short-term win
Run the same loan into a 15-year term and the payment rises instead of falling — the "saving" is negative, and the calculator reports no monthly gain. This is the comparison the payment view hides: a 15-year refinance usually loses money month to month and wins enormously over the term, because the rate is lower and the interest years are fewer.
Which one is right depends on the same question as ever: how long you stay. The 30-year refinance pays in fifteen months and costs more in total interest than the shorter original loan. The 15-year refinance costs more per month and ends years earlier with six figures saved.
The term reset nobody mentions
Refinancing a loan you are five years into, into a fresh 30-year term, restarts the clock. The payment drops partly because the balance is amortized over 360 new months instead of the 300 you had left. Those ten extra months of payments are invisible in the monthly comparison and enormous in the lifetime one.
The honest check is the net benefit over the term, which nets the saving against the costs — and against the term you gave up. If the number only works because the term stretched, the deal is smaller than it looks.
Frequently asked questions
Is the 1% rule real?
It is a shortcut that ignores balance, costs and horizon — the three inputs that decide everything. A 0.75% drop on a large balance with cheap costs beats a 1% drop on a small one. Compute the break-even instead.
Are no-cost refinances a trap?
They are a trade: the lender covers closing costs and charges a higher rate for the life of the loan. For someone who may move within a year or two, that trade can be right — the break-even arrives immediately. For a long stay, the extra rate compounds far past what the costs were worth.
Should I refinance to remove PMI too?
If the new appraisal puts you at 80% loan-to-value or better, the new conventional loan has no PMI — and that monthly saving belongs in the break-even alongside the rate saving. Add the PMI premium to the monthly saving and divide again.