What a refinance break-even point really means
The usual formula ignores the balance you stop paying down. That is where it goes wrong.
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Educational estimates only. Not financial, tax, or lending advice.
How is a refinance break-even point calculated?
Break-even is the month your accumulated savings finally exceed what the refinance cost you. The common formula divides closing costs by the monthly payment reduction, which ignores that a longer term pays principal down more slowly. Counting the balance you still owe gives a later break-even month, and a more honest one.
How do most calculators work out break-even?
Closing costs divided by the monthly payment reduction. Spend $6,000 to save $200 a month and the answer is 30 months.
It is easy to compute and easy to explain, which is why almost every lender and comparison site states it that way. It is also incomplete, because it treats the whole payment reduction as money saved.
Some of that reduction is not a saving at all. If the new loan stretches repayment over more years, part of what you stopped paying each month was principal — money that was reducing your debt. Stop paying it and the debt stops falling as fast.
What does that formula leave out?
The balance you still owe on the day you sell.
Two mortgages are only comparable if each is charged for the debt it leaves behind. Otherwise a loan can look cheaper purely by paying down more slowly, which is the deferral of a cost rather than the avoidance of one.
So this site measures break-even on total position: closing costs paid in cash, plus every payment made, plus the balance still owed, minus any cash received — compared against simply keeping your current mortgage. Break-even is the first month that total falls below the total for keeping.
Why does this site show two break-even figures?
Because ours disagrees with every other calculator you will check, and an unexplained disagreement reads as a bug.
The conventional figure counts only the monthly payment saving against the cash you pay upfront. Ours also counts what you still owe when you sell, which is why the two disagree.
| Conventional | This site | |
|---|---|---|
| Counts upfront cash | Yes | Yes |
| Counts monthly payment saving | Yes | Yes |
| Counts the balance still owed | No | Yes |
| Answer when the payment rises | None — the method yields nothing | Still an answer |
| Typical result | Earlier month | Later month |
Neither is a forecast. Both assume you keep the loan on the schedule shown and that the figures you entered hold.
The conventional method has a blind spot it concedes itself: where the new payment is higher than the current one, there is no payment saving to divide into, so it returns no break-even at all. A recast and extra principal are exactly those cases. Counting the balance still gives an answer for them.
What if I sell before I break even?
Then the refinance cost you money, even though the monthly payment went down.
This is the only input that reverses conclusions rather than merely moving them. A refinance that is clearly worthwhile over ten years can be clearly a loss over three, and nothing about the rate or the payment tells you which case you are in.
So the tool asks how long you expect to stay and prices every option over that period, rather than over a full term you may never reach. Where the break-even point falls after your horizon, it says so plainly instead of reporting a month you will never see.
What actually moves the break-even month?
Closing costs more than the rate, in most close decisions.
Closing costs are the numerator of the calculation, so they move the answer directly and immediately. A half-point better rate paired with high fees regularly loses to a slightly worse rate with low fees over a short horizon.
The term matters nearly as much, because it decides how much of the payment reduction is real. And whether you pay the costs in cash or finance them changes both the upfront figure and the balance, which is why the calculator asks.