A lower rate isn’t automatically a lower cost
Refinancing replaces your current loan with a new one, and that new loan comes with its own closing costs — typically 2 to 5% of the loan amount, covering origination fees, appraisal, title work, and similar costs. A lower rate saves you money every month, but you’re paying for that lower rate upfront. The break-even point is when your accumulated monthly savings finally exceed what you paid to get there.
How much does a lower rate actually save?
The table below holds this calculator’s default example constant — a $340,000 balance, current rate of 7.25% with 27 years remaining, refinancing into a new 30-year loan with $6,500 in closing costs — and varies only the new rate offered.
| New rate | New payment | Monthly savings | Breaks even in |
|---|---|---|---|
| 5.25% | $1,877.49 | $516.77 | 13 months |
| 5.75% | $1,984.15 | $410.11 | 16 months |
| 6.25% | $2,093.44 | $300.82 | 22 months |
| 6.75% | $2,205.23 | $189.03 | 35 months |
| 7.00% | $2,262.03 | $132.23 | 50 months |
The relationship isn’t linear — a small rate drop near your current rate takes disproportionately longer to break even than a larger one, since the fixed closing costs are being recouped against a shrinking monthly savings figure. This is the practical reason lenders and advisors commonly suggest waiting for at least a 0.75–1 percentage point drop before refinancing purely for payment savings.
The trap: resetting your term
The math above compares your remaining interest on the current loan against total interest on the new one — not against what you originally borrowed. This matters because refinancing often resets the clock: if you’re 3 years into a 30-year mortgage and refinance into a new 30-year loan, you’re extending your payoff timeline by 3 years, even though your new rate is lower. That can produce a lower monthly payment while still costing more in total interest over the life of the loan. The “net lifetime savings” figure above accounts for this directly — it’s possible for that number to be negative even when your monthly payment drops.
Understanding each input
Remaining balance
What you currently owe on your existing mortgage — not the original loan amount. This is the amount being refinanced.
Current rate & years remaining
Your existing loan’s rate and how many years are left on it. This calculator compares your remaining interest on this loan against the new loan, which is why years remaining (not your original term) is the correct figure to enter.
New rate & new term
The terms of the loan you’re being offered. If the new term is longer than your years remaining, you’re extending your payoff timeline — watch the “net lifetime savings” figure, which can go negative even when the payment drops.
Closing costs
Fees to originate the new loan — typically 2–5% of the loan amount, covering appraisal, title, origination, and similar costs. This is the upfront cost your monthly savings need to recoup before the refinance is worth it.
Why break-even time horizon matters more than the payment drop
A refinance that breaks even in 14 months is a very different decision than one that breaks even in 6 years, even if both lower your monthly payment by a similar amount. If you might sell or refinance again before the break-even point, you’ll never actually recoup the closing costs. Compare the break-even timeline above against how long you actually expect to stay in the loan.
When refinancing makes sense even without payment savings
Not every refinance is about lowering the payment. Refinancing from a 30-year loan into a 15-year loan at a similar or even higher payment can save substantial interest by shortening the payoff timeline — that’s a legitimate reason to refinance that this calculator’s “monthly savings” framing doesn’t fully capture on its own. Removing PMI, switching from an adjustable rate to a fixed rate, or a cash-out refinance for a specific purpose are also valid reasons that don’t hinge purely on the break-even math above.
Using this calculator
Get real numbers from a lender rather than estimating your closing costs — that figure varies enough by lender and loan size that a rough guess can meaningfully shift your break-even point. Enter your loan’s actual remaining balance and years left, not the original loan terms, since refinancing only affects what you still owe going forward.
This article is for educational purposes only and isn't legal, financial, or tax advice. See our Disclaimer for details.
