Tesserae ← All tools Open Tesserae

Free calculator · no signup · runs in your browser

Refinance Break-Even Calculator

A refi is a bet that you'll keep the loan long enough for the monthly savings to pay back the closing costs. This computes the break-even month — and the comparison lenders skip: whether the new loan really costs less over its life, once the term reset is counted.

$
%
yrs
%
yrs
$
yrs

Break-even

 

Monthly savings

New payment (P&I)

Lifetime interest, after costs

The lifetime tile compares loans of different lengths — all remaining interest on the current loan vs. all interest over the new one, closing costs included. That mismatch is the point of the comparison, but keep it in mind.

Worth knowing: the refi only pays off if you keep the loan past the break-even — moving or refinancing again before then means the closing costs never get recouped. And "no-closing-cost" offers just move the costs into the rate or the balance; the lifetime comparison is where that shows up.

The two questions a refi has to answer

Question one: how fast do I get my money back? Closing costs are paid up front; savings arrive monthly. Divide one by the other and you get the break-even month. Before it, the refi has cost you money; after it, every month is profit. The whole decision compresses into one comparison — break-even month vs. how long you'll realistically keep this loan. Most people don't keep a 30-year loan for 30 years; if your break-even is 4 years and you might move in 3, the "savings" are a loss.

Question two: does the new loan cost less over its life? This is where the term reset hides. Refinance 26 remaining years into a fresh 30-year loan and the payment drops for two reasons — the lower rate (real savings) and six extra years of stretching (an illusion of savings). A refi can win the monthly comparison and lose the lifetime one. The amber warning above fires whenever your inputs do exactly this.

The formulas

break-even months = closing costs ÷ (old P&I − new P&I)

Each payment comes from the standard amortization formula on the same remaining balance. Lifetime comparison: interest left on the current loan (old payment × months left − balance) vs. interest over the whole new loan, minus closing costs.

Beating the term reset

Two clean fixes if the lifetime number turns against you: refinance into a shorter term (a 15- or 20-year usually carries a lower rate than the 30 as well), or take the 30-year and keep paying your old payment — the difference becomes extra principal, the payoff date stays roughly put, and you've captured the rate cut without the stretch. The second option also keeps the lower payment available as a safety valve in a tight year.

Common questions

How big a rate drop is worth refinancing for?
The old "1% rule" (only refinance if the rate drops a full point) is a rough proxy for what actually matters: the break-even math. A 0.5% drop on a large balance can break even quickly; a 1.5% drop on a small balance might not. Run the numbers — the rule of thumb was only ever a shortcut for this division.
Should I pay points for a lower rate?
Points are prepaid interest — the same break-even logic applies, just with a longer horizon. Add the points to the closing costs here and see the new break-even; points typically only pay off if you keep the loan well past it (often 5–7+ years).
What about a cash-out refinance?
Different decision — you're borrowing more, not just repricing. The break-even framing doesn't apply cleanly, and the new (usually higher) rate applies to the whole balance, not just the cash taken out. Compare against a HELOC or home-equity loan before committing.
Do I have to refinance with my current lender?
No — and shopping matters more than people expect. Rate and fee spreads between lenders on the same borrower routinely move the break-even by months. Get at least three quotes on the same day (rates move daily) and compare the loan estimates line by line.

See the refi inside your whole plan

Tesserae tracks the mortgage next to everything else — the payment's effect on monthly cash flow, your net worth, and the retirement date. Privacy-first: you enter your own numbers, and we never touch your bank login.