Resetting the clock is a hidden cost. If you're 8 years into a 30-year mortgage and refi into another 30-year, you've added 8 years of payments. The monthly may be lower, but lifetime total often rises. Try a refi into the remaining term, not a fresh 30. Closing costs vary wildly. Typical US: 2–5% of loan amount. UK product fees: £500–£2,000. Always get a Loan Estimate (or equivalent) in writing before trusting the upfront number. Points = pre-paid interest. Buying 1 point (1% of loan) typically cuts the rate by ~0.25%. Worth it only if you'll keep the loan long enough — usually 3+ years. Tax effects. US mortgage interest is deductible if you itemize. A refi reduces deductible interest, so the after-tax savings may be smaller than the headline figure. Talk to a tax professional for your situation. Cash-out refis are different. If you're pulling equity out, the comparison isn't apples-to-apples — you're taking new debt, not just swapping the existing. Variable rate vs fixed. Swapping a fixed-rate for a variable to capture today's lower rate is a forecast bet on rates staying low. This tool assumes both loans are fixed. Prepayment penalties. Some older loans charge a fee for paying off early. The refi has to clear that, too. Not modelled here.

loan-calculator — full month-by-month amortization once you've picked a path. compound-interest-calculator — compare investing the monthly savings instead. mortgage-affordability-calculator — sanity-check the new payment against income.

Mortgage Refi Comparison

Compare your current mortgage to a refinance offer. See break-even point, monthly payment difference, total lifetime savings. Account for closing costs.

Doesn't account for prepayment penalties on your existing loan, mortgage tax deductions, or changes to your effective tax rate. Use as a first-pass comparison, not as financial advice.

Current mortgage

Balance remaining

Current rate (annual %)

Years remaining

Currency symbol

Refinance offer

New rate (annual %)

New term (years)

Closing costs

Discount points (1 pt = 1% of new principal)

Result

Understanding the results

When mortgage rates drop, lenders pitch a refinance: a new loan that pays off your existing one at a lower rate. The lower rate is nice, but closing costs and a fresh start on amortization complicate the picture. This tool answers the only question that matters: over the life of the loan, do I come out ahead? And if so, after how many months of saved payments does the math actually flip positive?

The break-even calculation

Closing costs and discount points are paid up front. Each month, the refi's lower payment saves you a fixed amount. Break-even month is simply upfront cost / monthly savings, rounded up. After that month, every additional payment is pure savings — until either loan finishes amortizing.

Lifetime savings

Total payments on the current loan (monthly × remaining months) minus total payments on the refi loan (monthly × new months + upfront cost). If positive, the refi wins over the full term. If you sell or refinance again before that horizon, the comparison resets — break-even month is the more relevant single number for short-horizon refis.

Common gotchas

Resetting the clock is a hidden cost. If you're 8 years into a 30-year mortgage and refi into another 30-year, you've added 8 years of payments. The monthly may be lower, but lifetime total often rises. Try a refi into the remaining term, not a fresh 30.
Closing costs vary wildly. Typical US: 2–5% of loan amount. UK product fees: £500–£2,000. Always get a Loan Estimate (or equivalent) in writing before trusting the upfront number.
Points = pre-paid interest. Buying 1 point (1% of loan) typically cuts the rate by ~0.25%. Worth it only if you'll keep the loan long enough — usually 3+ years.
Tax effects. US mortgage interest is deductible if you itemize. A refi reduces deductible interest, so the after-tax savings may be smaller than the headline figure. Talk to a tax professional for your situation.
Cash-out refis are different. If you're pulling equity out, the comparison isn't apples-to-apples — you're taking new debt, not just swapping the existing.
Variable rate vs fixed. Swapping a fixed-rate for a variable to capture today's lower rate is a forecast bet on rates staying low. This tool assumes both loans are fixed.
Prepayment penalties. Some older loans charge a fee for paying off early. The refi has to clear that, too. Not modelled here.

Pairs with

loan-calculator — full month-by-month amortization once you've picked a path.
compound-interest-calculator — compare investing the monthly savings instead.
mortgage-affordability-calculator — sanity-check the new payment against income.

Worked example

Your current payment is $1,600/month; the refinance offer drops it to $1,430/month, saving $170 a month. Closing costs come to $4,200. Break-even = 4,200 ÷ 170 = 25 months. Stay in the home past roughly two years and every payment after that is real savings; sell or refinance again before month 25 and the deal cost you money despite the lower rate.

FAQ

Break-even month or lifetime savings — which should I trust? If there's any chance you'll move or refinance again within a few years, break-even is the number that matters. If you're settled for the long haul, lifetime savings captures the full picture.

Should I refinance into a shorter term? Often, yes. Refinancing eight years into a 30-year loan back into a fresh 30-year resets the clock and can raise your lifetime total even at a lower rate. Compare a refi into your remaining term before defaulting to another 30.

What belongs in "closing costs"? Lender/origination fees, appraisal, title, and any discount points — typically 2–5% of the loan in the US. Roll them all in, because they're what the monthly saving has to earn back.

Does it account for the mortgage-interest tax deduction? No — it compares pre-tax cash flows. If you itemise, the deduction slightly narrows the gap between the two loans, but it rarely changes which one wins.

How it works

The core number is the break-even month = closing costs ÷ monthly saving. Refinance from a $1,600 payment to $1,430 saves $170 a month; $4,200 in closing costs divided by $170 is about 25 months to recover the cost. Every payment after that is real money; sell or refinance again before the break-even and the lower rate still lost you money. The subtler factor is the term reset: refinancing eight years into a 30-year loan back into a fresh 30-year restarts the amortization clock, so you pay interest for longer and can raise your lifetime cost even at a lower rate — which is why the tool reports both break-even and total lifetime figures.

Common mistake

Judging a refinance only on the drop in monthly payment. A lower payment stretched over a fresh 30-year term can cost more overall than the loan you already have. Compare a refi into your remaining term, not automatically another 30 years, and make sure the monthly saving clears the closing costs within the time you actually plan to keep the home.

Check the underlying payment and schedule with the loan calculator, and re-test affordability if your situation changed with the affordability calculator. The timing logic in depth: when to refinance — the breakeven math.