Every time rates drop, my phone lights up with the same question: should I refinance? Sometimes the answer is obvious. Usually it's not. The honest version requires doing the math — and being willing to walk away if the math doesn't work.
The break-even calculation
Take the total cost of the refinance (lender fees, title, appraisal, prepaids) and divide by your monthly savings. That's how many months it takes to break even. If you plan to keep the home longer than that, refinancing probably makes sense. If you don't, it probably doesn't. This is the whole calculation, and it takes five minutes.
A worked example
Let's run an actual scenario. You took out a $350,000 mortgage at 7.25% three years ago. Rates have dropped to 6.0%. Should you refinance?
Step 1: estimate your monthly savings
On the original $350,000 at 7.25%, your monthly principal-and-interest payment is roughly $2,388. After three years of payments, your remaining balance is around $337,000. Refinancing $337,000 at 6.0% on a fresh 30-year drops the principal-and-interest payment to about $2,021. Monthly savings: roughly $367.
Step 2: estimate refinance costs
Refinance closing costs typically run $4,000–$6,000 on a loan of this size in NC, depending on lender fees, title charges, and prepaids. For this example, call it $5,000.
Step 3: divide costs by monthly savings
$5,000 divided by $367 in monthly savings = roughly 14 months to break even. If you plan to keep the home longer than 14 months, the refinance pays off. If you might move in less than that, it doesn't.
Cash-out refinance math is different
If you're pulling equity out for a real purpose — paying off high-interest debt, funding a renovation that adds value — the break-even math shifts. You're not just comparing rates, you're comparing the all-in cost of capital against your alternatives. Sometimes the rate goes up slightly and the refi still makes perfect sense.
Example: replacing $30,000 of credit card debt at 22% APR by adding it to your mortgage at 6%. Even if your new mortgage rate is slightly higher than your old one, the savings on the credit card interest alone usually justifies the move — provided you don't run the cards back up. The discipline question matters as much as the math.
Scenarios where it doesn't pay
Refinancing isn't free, and the marketing around "how much you'll save" usually skips the situations where the math turns negative. Here are the cases where I tell clients to stay put.
You're 10+ years into a 30-year loan
Even at a meaningfully lower rate, resetting your amortization clock back to 30 years often costs more total interest than just paying the existing loan to term. If the refi-to-30 saves $150 a month but adds $40,000 in lifetime interest, that's not a win. A refinance into a 15- or 20-year term can fix this — but only if the new payment fits your budget.
Your rate drop is under 0.5%
On most loan sizes, a sub-50-basis-point rate drop produces a break-even period that's longer than most homeowners stay in their home. Wait for a bigger drop or a meaningful change in your situation (cash-out need, term change, removing PMI).
You might move in the next 18 months
Refinance break-even is typically 12–24 months on a meaningful rate drop. If you're likely to move sooner, you'll pay closing costs to set up a loan you'll abandon before recouping them. The exception is a free or near-free streamline refinance — which exists for some VA and FHA loans.
Removing PMI is the only goal
If you've hit 20% equity on a conventional loan and your only motivation is dropping PMI, you usually don't need a full refinance. Request automatic PMI cancellation from your servicer once you reach 78% LTV (or request it at 80%). That's a phone call, not a $5,000 transaction.
Common refinance mistakes
- Refinancing every time rates dip without recalculating the break-even.
- Rolling closing costs into the loan and forgetting that you're now paying 30 years of interest on those costs.
- Resetting a 30-year loan you're 10+ years into without considering a 15- or 20-year refi instead.
- Cash-out refinancing to pay off debt without changing the spending pattern that created the debt.
- Not shopping the refi — the lender who originated your purchase isn't automatically the best refi option.
Special case: VA streamline refinance (IRRRL)
If you have an existing VA loan, the Interest Rate Reduction Refinance Loan (IRRRL) is meaningfully cheaper than a full refinance. No new appraisal in most cases, no income re-verification, lower closing costs, and a lower funding fee than a typical refi. The break-even math on an IRRRL is usually a fraction of a conventional refinance — often single-digit months.
What to do next
If you're considering a refinance, send me your current loan amount, current rate, current monthly payment (principal and interest only), and the rate you're being quoted. I'll run the actual break-even and tell you honestly whether it's worth doing. The best refinance is sometimes the one you skip — and you deserve a lender who'll tell you that.
