Test 1: the break-even month
Closing costs (typically 2–6% of the balance — appraisal, origination, title, recording) are paid up front; savings arrive monthly. Divide one by the other: $5,000 ÷ $284 ≈ month 18. Sell or refinance again before that month and the deal lost money, no matter how good the rate looked. Be pessimistic about how long you'll really stay — the average homeowner moves far more often than they predict at closing.
Test 2: the lifetime cost (where the term reset hides)
A lower payment can still cost more overall, because refinancing a loan with 26 years left into a fresh 30-year adds four years of payments to the end. Our example passes anyway ($11,578 lifetime savings) because the rate drop is large — but shrink it to a quarter point and the reset quietly eats the benefit. Always compare remaining interest on the old loan vs total interest on the new one plus costs; the calculator prints exactly that table.
The upgrade most people miss: refinance shorter
Same example, but into a 20-year at 5.9%: the payment is $1,776.68 — just $-6 more than today's — while lifetime savings jump to $124,769 versus $11,578 for the 30-year version. When income has grown since you bought, a shorter-term refinance converts a rate drop into years of freedom instead of monthly pocket money. (Related: the 15-vs-30 guide.)
"No-closing-cost" refinances, decoded
There's no free version — the costs move into either the balance (you finance them, with interest, for decades) or the rate (a "lender credit" priced ~0.25–0.5% higher). Both are testable: model financed costs with the calculator's checkbox, or set costs to $0 and enter the higher quoted rate. Sometimes the no-cost version genuinely wins — short expected stays favor it — but decide with the math, not the label.
Reasons to refinance that aren't about the payment
- Killing FHA MIP: once you reach ~20% equity, refinancing to conventional removes life-of-loan mortgage insurance — often worth more than the rate change (see PMI explained).
- Escaping an ARM before reset, trading rate uncertainty for a fixed schedule.
- Cash-out for renovations or consolidation — a different decision with different risks: you're re-collateralizing other spending with your house.
When to walk away
Skip the refinance if the new payment isn't lower and no structural goal (shorter term, MIP removal, ARM escape) applies; if you're within a couple of years of moving; or if you'd stretch a nearly-paid loan back to 30 years for grocery-money savings. The math is unforgiving in both directions — which is exactly why we show the break-even month and the lifetime table side by side in the refinance calculator.