How to calculate your refinance break-even point (and when it misleads)

Short answer: divide the total cost of refinancing by the monthly payment saving. If refinancing costs $6,000 and saves $283 a month, you break even in about 21 months. It is only worth it if you keep the new loan longer than that — and you should also compare total interest, because a new 30-year term can hide extra cost.

The break-even formula

Break-even (months) = total refinance costs ÷ (current monthly P&I − new monthly P&I)

Use principal and interest only — taxes and insurance don’t change when you refinance. Include every cost: lender fees, points, appraisal, title, recording, and any costs financed into the new loan.

A worked example

A homeowner owes $320,000 at 7.25% with 27 years left. Their P&I is $2,253.42.

They’re offered a new 30-year loan at 6.25% for the same $320,000, with $6,000 in costs.

• New P&I: $1,970.30
• Monthly saving: $2,253.42 − $1,970.30 = $283.12
• Break-even: $6,000 ÷ $283.12 ≈ 21.2 months

If they stay more than two years, the refinance pays for itself.

Where the simple break-even misleads

The example also resets the clock from 27 years to 30. Part of the lower payment comes from stretching the loan, not just the lower rate. So compare total interest too:

Here the refinance still wins by about $20,800 over the full term. But with a smaller rate drop, stretching the term can mean paying more interest overall even though the payment falls.

Two fixes:

• Choose a shorter term. A 25-year loan at the same 6.25% has a P&I of $2,110.94 — a smaller saving ($142.48, break-even about 42 months) but it keeps the payoff date close to the original.
• Keep paying the old amount. Refinance to 30 years for flexibility, then pay the old $2,253 voluntarily to pay the loan off years early.

Points, lender credits and the break-even

Paying discount points raises upfront cost to buy a lower rate, lengthening break-even. Lender credits do the opposite. Ask for two or three pricing options and run each: the lowest rate is not always the best deal for someone who might move in four years.

Cash-out refinances are a different question

A cash-out refinance replaces your whole mortgage to release equity. The right comparison is against a HELOC or home equity loan that leaves your current first-mortgage rate untouched — especially if that rate is low.

Using a refinance calculator on your site

Borrowers see rate headlines and wonder if they should act. A refinance calculator that shows the monthly saving, the break-even month and the lifetime interest difference answers that honestly — and a “Get a Quote” action turns the interested ones into leads. CalcFunnel’s refinance calculator reports all three, alongside new loan amount and loan-to-value.

Estimates only. Your break-even depends on the actual rate and costs you’re offered.