Every refinance decision, underneath the noise, is one comparison: what it costs to refinance versus what refinancing saves you. Get those two numbers and divide, and you have your answer — a break-even point in months. Refinancing is worth it if you'll keep the loan past that point. Almost everything else is commentary.
The core calculation
If refinancing costs $6,000 and drops your payment by $300 a month, you break even in 20 months. Stay in the loan longer than that and every month afterward is pure savings; leave sooner and you lost money on the deal. Simple — but there's a subtlety in the “savings” number that trips up almost everyone, covered below.
A worked example, start to finish
Take a realistic 2026 case: you bought near the rate peak and can now refinance down.
$400,000 at 7.75%, two years in, refinance to 6.50%
A 1.25-point drop on a large balance produces a big monthly saving and a fast break-even. On these numbers the refinance is clearly worth doing. But notice the new loan is a fresh 30-year term — and that's where the hidden cost lives.
The trap: resetting the clock
When you refinance into a new 30-year loan, you restart the amortization clock. You were two years into a 30-year loan — 28 years to go — and you just reset to 30. Those two extra years of payments are real money, and a lower monthly payment is very good at hiding them.
Both refinances save money — the rate drop is real. But refinancing into a fresh 30-year term captures only $69,299 of interest savings, while refinancing into a loan that keeps your original payoff date captures $109,146. The lower monthly payment of the 30-year option feels better, and costs about $40,000 more over time. That's the reset-the-clock trap.
Keeping your payoff date
There are two clean ways to avoid giving back years:
- Refinance into a shorter term that matches (or beats) your remaining payoff date. If you have 28 years left, refinance into a 25- or 20-year loan. The payment saving is smaller than a 30-year would show, but you keep far more of the interest benefit — and often the shorter term carries a slightly lower rate too.
- Refinance into a 30-year, but keep paying the old amount. Take the new lower required payment, then voluntarily pay what you paid before (or your original payoff-date amount). You get the flexibility of the lower required payment with the interest savings of the shorter term — the logic in making extra payments.
The point isn't that resetting the clock is always wrong — a lower required payment can be exactly what you need for breathing room. The point is to see the trade, so you're choosing it rather than stumbling into it.
Why '1% rule' thinking fails
You'll hear that refinancing is worth it once rates drop “1%” (or 0.5%, or 2%, depending who's talking). These rules of thumb are unreliable because they ignore the two things that actually decide it: your balance and how long you'll keep the loan.
A 0.5% drop on an $800,000 balance saves far more per month than a 1% drop on a $150,000 balance, so the same “rule” gives opposite answers. And any rate drop is worthless if you sell before the break-even. Ignore the rules of thumb and run the actual break-even for your actual numbers — it takes a minute and it's the only thing that's true for your loan.
Don't forget the costs inside the loan
One last precision. If you roll the closing costs into the new balance instead of paying them up front — or take a no-closing-cost refinance — your break-even math changes. Rolling costs in means you're financing them, so the “cost” side of the calculation includes the interest you'll pay on them. And a no-cost refinance trades the up-front fee for a higher rate, which shrinks your monthly saving and pushes the break-even out. Whichever structure you choose, get the Loan Estimate, use the real payment difference, and let the break-even — not a rule of thumb or a lower sticker payment — make the call.
Frequently asked questions
How do I calculate my refinance break-even?
Divide the total closing costs of the refinance by the amount your monthly payment drops. The result is the number of months to recoup the cost. If you'll keep the loan longer than that, refinancing pays; if you'll sell or refinance again sooner, it doesn't.
Does refinancing reset my loan term?
It does if you refinance into a new 30-year loan — you restart the amortization clock, adding back the years you'd already paid down. That lowers your monthly payment but can cost tens of thousands in extra interest. To avoid it, refinance into a shorter term matching your remaining payoff, or keep paying your old amount.
Is the '1% rule' for refinancing accurate?
No. Rules of thumb like 'refinance when rates drop 1%' ignore your balance and how long you'll keep the loan — the two things that actually decide it. A small drop on a large balance can be very much worth it, while a large drop is worthless if you sell before the break-even. Run the real numbers instead.
Should I refinance into a shorter term or keep the 30-year?
A shorter term keeps more of the interest savings and often carries a lower rate, at the cost of a higher required payment. A 30-year gives a lower required payment and more flexibility. A middle path: take the 30-year but voluntarily pay your old amount, capturing both the flexibility and most of the savings.
Does rolling closing costs into the loan change the break-even?
Yes. Financing the costs means you pay interest on them, so they cost more than their sticker amount, and a no-closing-cost refinance trades the fee for a higher rate that shrinks your monthly saving. Both push the break-even further out, so use the real payment difference from your Loan Estimate.
Mortgage Ledger publishes educational information, not personalized financial, legal, tax, lending, or investment advice. The figures here are estimates built on stated assumptions and will not match a lender’s underwriting exactly. Confirm any number that matters against your Loan Estimate and a licensed professional before you act on it.