Lenders advertise refinances on monthly savings — "save $400 a month!" — and most homeowners decide based on that headline figure. But the savings only matter if they outlast the closing costs. The break-even point is the month when accumulated monthly savings finally exceed what you paid to refinance, and it's the single number that determines whether your refinance is a good deal or a costly mistake. Here's how to calculate it correctly, including the cases where the simple formula doesn't apply.
The basic formula
The standard refinance break-even calculation is one division problem:
Break-even months = Closing costs ÷ Monthly savings
Stay in the home longer than the break-even? The refi is a winning trade. Sell or refinance again before break-even? You lost money on the transaction.1
A worked example
- Current loan: $620,000 at 7.50%, monthly P&I = $4,335
- New loan: $620,000 at 6.23%, monthly P&I = $3,810
- Monthly savings: $525
- Closing costs: $9,300 (1.5% of loan amount)
- Break-even: $9,300 ÷ $525 = 17.7 months (about 18 months)
If this homeowner stays in the home and keeps the loan for at least 18 months, they're net ahead. If they sell at month 12, they paid $9,300 in closing costs and saved only $6,300 — a net loss of $3,000. The 18-month threshold isn't a guideline; it's the exact line between gain and loss.
What goes in "closing costs"
Refinance closing costs typically run 2-5% of the loan balance.2 The line items:
| Cost category | Typical range on a $620K refinance |
|---|---|
| Origination/lender fees | $2,500–$6,200 |
| Appraisal | $500–$900 |
| Title insurance (lender's policy) | $1,000–$1,800 |
| Escrow/settlement fees | $700–$1,500 |
| Recording fees | $50–$300 |
| Credit report, flood cert, misc. | $100–$300 |
| Discount points (optional) | 0–2%+ of loan |
| Prepaid items (interest, escrow) | $1,500–$4,000 |
| Total typical range | $6,350–$15,000 |
The wide range comes from origination structure (some lenders charge 1% of loan, others charge nothing and bake compensation into a higher rate) and discount points (entirely optional).
Lenders advertising "no closing cost refinances" are doing one of two things: rolling fees into the loan balance (you pay them with interest over 30 years) or charging a higher rate (typically 0.125%–0.25% above market) to cover their costs. Both still cost real money. More on the no-cost refi myth. For a true apples-to-apples break-even, calculate using the actual rate you're offered with each fee structure.
What goes in "monthly savings"
This is where most break-even calculations go wrong. The right number is the difference in principal-and-interest payments only, not the difference in total monthly payment.3
Property tax and homeowners insurance don't change just because you refinanced — those bills are based on your home's value and your insurance policy, not your loan. If your old payment was $5,200 (P&I $4,335 + escrow $865) and your new payment is $4,675 (P&I $3,810 + escrow $865), the savings are $525, not $525 plus some inflated escrow figure.
Lenders sometimes structure new escrow accounts differently than old ones, making the total payment look very different even when the underlying P&I savings are modest. Always reduce both old and new payments to P&I-only before subtracting.
The cases where the simple formula breaks down
Shortening the loan term
If you refinance from a 30-year to a 15- or 20-year loan, your monthly payment may go up, not down — even at a lower rate. The simple formula gives you a negative break-even point or doesn't compute at all.
The right way to evaluate: compare interest costs, not total payments. Example:
- Existing: 30-year at 7.5%, $620K balance, paying $3,875 in interest in month 1
- New: 20-year at 6.0%, $620K balance, $9,000 closing costs, paying $3,100 in interest in month 1, $4,442 P&I total (vs. $4,335 old)
- Monthly P&I increases $107, but interest costs drop $775/month
- Break-even on interest savings: $9,000 ÷ $775 = 11.6 months
This refinance saves substantial money over the life of the loan despite a higher monthly payment. The simple "monthly payment savings" formula misses it entirely.
Cash-out refinances
Cash-out refinances usually increase your monthly payment. The break-even formula doesn't apply directly — you're not saving money each month, you're trading a lump sum of cash for higher monthly payments. More on cash-out evaluation.
Resetting the amortization clock
Refinancing year 8 of a 30-year loan into a fresh 30-year loan extends total payoff to 38 years and dramatically increases lifetime interest, even if your monthly payment drops.
To capture this in break-even math, calculate not just monthly savings but also net interest savings over your expected hold period:
- Calculate total interest you'll pay on the existing loan over your expected hold period.
- Calculate total interest on the new loan over the same hold period (using the new amortization schedule starting from month 1).
- Net interest savings = old total − new total.
- True break-even = closing costs ÷ (interest savings ÷ months held)
For most rate-drop refinances early in the loan term, the simple formula is close enough. For refinances late in the loan term, the more rigorous approach reveals that "savings" can actually be losses.
How long is "long enough"?
Common break-even thresholds and how to think about them:
| Break-even months | Decision rule |
|---|---|
| Under 24 months | Almost always worth it for a typical hold |
| 24–48 months | Worth it if you'll stay 5+ years |
| 48–72 months | Marginal — only if confident in 7+ year hold |
| Over 72 months | Rarely worth it — too much depends on staying put |
San Diego homeowner tenure is longer than the national average — Redfin data suggests typical tenure runs 11+ years. That tilts the math toward refinancing being worthwhile even at 48-60 month break-evens — but only for owners who genuinely plan to stay.
The 1% rule of thumb (and why it's incomplete)
The traditional advice — "refinance when rates drop 1% below your current rate" — is a reasonable starting filter but a bad final answer. It ignores:
- Loan size. A 1% drop on a $1M loan saves dramatically more dollars than a 1% drop on a $250K loan.
- Closing costs. Same 1% drop with $5K closing costs vs. $15K closing costs produces very different break-evens.
- Hold period. 1% drop with a planned 3-year hold versus a 15-year hold are entirely different decisions.
- Term changes. A 1% drop combined with a term shortening is materially better than a 1% drop with same term.
Always run the actual break-even calculation. The 1% rule is a screening filter, not a decision rule.
Two common timing mistakes
Mistake 1: Waiting for "rates to drop more"
Homeowners frequently wait when their break-even is already attractive, hoping for an even better rate. Two problems with this:
- Rates can move either direction. The window can close before it widens.
- Each month you wait at the higher rate is a month of unrealized savings. Even if you eventually catch a 0.25% better rate, you've given up months of $400-$500 savings to do it.
Mistake 2: Refinancing too soon after purchase
Most cash-out and conventional rate-and-term programs have a 6-month seasoning requirement. Trying to refinance within 6 months of purchase typically isn't possible regardless of how much rates have moved. Plan timing accordingly.
Run a break-even calculation on your specific scenario.
Open the calculator →The honest read
The break-even calculation is the central question of every refinance decision. Don't let lenders sell you on monthly savings without also showing you the closing costs and the break-even months. Don't let "no closing cost" advertising fool you into thinking the costs disappear — they're either rolled into the loan or built into a higher rate. And for refinances late in your loan term, run the more rigorous net-interest-savings calculation rather than the simple monthly-savings formula. The right refi is one that pays back its costs well before you sell or refi again. Anything else is a transaction that benefits the lender more than you.
Closing costs and rate quotes vary by lender. Always run actual figures from a Loan Estimate before deciding. Educational content only — not legal, tax, or financial advice.
References
- Consumer Financial Protection Bureau. (n.d.). Should I refinance? Retrieved April 28, 2026, from https://www.consumerfinance.gov/owning-a-home/loan-estimate/
- NerdWallet. (2026). How to calculate the break-even point on a mortgage refinance. Retrieved April 28, 2026, from https://www.nerdwallet.com/mortgages/learn/if-you-refinance-a-mortgage-when-will-you-break-even
- Freddie Mac. (2026, April 23). Primary Mortgage Market Survey: U.S. weekly mortgage rate averages. https://www.freddiemac.com/pmms