Mortgage Refinance Calculator
See what a refinance does to your monthly payment and to the total interest you’ll pay — plus how long you have to keep the loan for the closing costs to pay for themselves.
Monthly payment
−$385.99
$2,253.42$1,867.43
Lifetime interest
−$51,832.41
$410,108.34$352,275.93
Break-even
16 months
How long you must keep the loan for $6,000.00 of closing costs to pay for themselves.
New loan
$320,000.00
Matches your current balance. $6,000.00 due at closing.
Your current loan
Today's payoff amount, not the original loan amount.
Original term minus the years you've already paid.
The refinance you're offered
Origination, appraisal, title, and recording fees. Typically 2–5% of the loan.
No cash at closing, but you finance the fees and pay interest on them for the whole term.
Side by side
Payments shown are principal and interest only. Your actual monthly bill also includes property tax, homeowners insurance, and any HOA dues or mortgage insurance, none of which a refinance changes.
Three numbers decide a refinance
The first is the monthly payment change, which is what most calculators stop at. The second is the lifetime interest change, which is where refinances quietly go wrong: a lower rate on a longer term routinely raises what you pay in total even as the monthly bill falls. The third is the break-even point — how many months of savings it takes to recover your closing costs. If you might sell or refinance again before that date, the deal loses money no matter how good the rate looks.
The term-extension trap
Say you’re eight years into a 30-year mortgage. You have 22 years left, and a lender offers you a lower rate on a fresh 30-year loan. The payment drops, so it reads as a win — but you’ve just added eight years of interest payments to the back of the loan, and that usually costs more than the better rate saves.
There are two clean ways around it. Refinance into a term at or below your remaining years — a 20-year or 15-year loan — so the clock doesn’t restart. Or take the 30-year for the flexibility of the lower required payment, then voluntarily keep paying the old, higher amount; the extra goes straight to principal and you capture most of the interest savings while keeping a lower floor for bad months. This calculator flags the trap whenever your payment falls but your lifetime interest rises.
Paying closing costs in cash versus rolling them in
Rolling closing costs into the loan means no money at the closing table and no break-even period to worry about — but you finance those fees at your mortgage rate for the entire term, which can nearly double their real cost over 30 years. Paying in cash is cheaper overall provided you keep the loan past break-even. If cash is tight, or there’s a real chance you move within a few years, rolling them in is often the more sensible choice even though it costs more on paper.
What this calculator leaves out
- Property tax, homeowners insurance, HOA dues, and mortgage insurance — a refinance generally doesn’t change these, so they’re excluded to keep the comparison clean. The exception: crossing the 80% loan-to-value line can add or remove mortgage insurance.
- Cash-out refinances, where you increase the balance to take equity out. Enter the higher post-cash-out balance to approximate one.
- Adjustable rates, interest-only periods, points buydowns, and prepayment penalties.
- Tax effects. Mortgage interest may be deductible — on a primary residence within federal limits, or as a business expense on a rental — which changes the after-tax value of any interest saved.
Frequently asked questions
Educational tool only. Payments shown are principal and interest only and assume a fixed rate held to term. Verify every figure against your actual Loan Estimate before deciding. Not financial, tax, or legal advice.