How the break-even calculation works
Refinancing costs money up front to save money monthly. Whether the trade is profitable depends on time — specifically, whether you keep the loan longer than the break-even point:
Break-even months = closing costs ÷ monthly savings
- Spend $6,000 on closing costs and save $370 a month → break-even in about 16 months.
- Every month past break-even is money in your pocket; sell the home a year earlier and the refinance lost you money despite the lower rate.
- The classic rule of thumb: break-even under 24 to 36 months is a strong candidate.
Worked example: dropping from 7% to 5.75% on a $300,000 balance
A borrower with $300,000 remaining at 7% and 25 years left pays about $2,120 a month. Refinancing the same balance at 5.75% over a fresh 30 years cuts the payment to roughly $1,751 — about $370 a month of relief. With $6,000 of closing costs, the break-even lands near 16 months. Over the full term, however, the two loans cost nearly the same in total interest, because the new loan adds five extra years of payments. The real win here is monthly cash flow, not lifetime savings.
The hidden cost of a reset term
This is the trap most refinance pitches gloss over. If you are eight years into a 30-year loan, you have already paid the front-loaded interest and are finally attacking principal. Refinancing into a new 30-year loan restarts that expensive clock — the lower rate helps, but the extra years of payments quietly eat the benefit. Two moves preserve the win: choose a new term that matches your remaining years, or keep paying the old (higher) amount on the new loan so the balance burns down ahead of schedule.
When refinancing is not worth it
- The payment rises: refinancing into a shorter term at only a slightly lower rate can cost you monthly. That can still be a deliberate wealth-building move — but go in with open eyes.
- You may move soon: a job change, growing family or relocation inside the break-even window makes the closing costs a loss.
- The rate gap is thin: lenders quote the benefit of a 0.25% drop; on a $300,000 balance that is roughly $45 a month — closing costs take years to recover.
- Cash-out temptation: refinancing to pull equity for spending converts secured home debt into consumption and stretches your payoff. This calculator assumes a rate-and-term refinance only.
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