Refinance Calculator
Compare your current mortgage to a new rate and find the break-even point.
Results update as you type.
About this calculator
A refinance calculator compares your current mortgage payment with a new loan at a different rate and term, then divides your closing costs by the monthly saving to find the break-even point — how long you must keep the new loan for the refinance to pay off. Sell or refinance again before then and it may not have been worth it.
It re-amortises your current balance under both loans. For example, a 250,000 balance with 25 years left at 6.5% costs about 1,688 a month; refinancing into a new 30-year loan at 5.5% drops the payment to roughly 1,419, a saving near 269 a month. With 4,000 in closing costs, you break even in about 15 months — after that the saving is yours, assuming you stay in the home.
Use it to judge whether today’s rates justify refinancing and to weigh a lower rate against a longer term. One trap the tool highlights: resetting a 25-year balance into a fresh 30-year loan lowers the monthly payment but can raise total interest, so compare lifetime cost, not just the monthly figure.
Frequently asked questions
How does the break-even point work?
Break-even months = closing costs ÷ monthly saving. If refinancing saves 180 a month and costs 4,000, you break even in about 22 months; keep the loan longer than that and you come out ahead.
Can extending the term erase the saving?
Yes. Refinancing a 25-year balance into a fresh 30-year term lowers the monthly payment but stretches repayment out, so you can pay more total interest even at a lower rate. Compare total cost, not just the monthly figure.
How much lower does the rate need to be to refinance?
There is no fixed threshold — what matters is whether the monthly saving recovers the closing costs before you move or refinance again. A common rule of thumb is at least 0.5–1% lower, but the break-even here is the real test.
What are typical refinance closing costs?
They usually run about 2–5% of the loan balance and cover lender fees, appraisal, title and taxes. Some lenders offer a "no-cost" refinance that rolls these into the rate or balance instead, which raises the break-even but avoids upfront cash.
Should I refinance to a shorter term?
If you can handle the higher payment, refinancing to a shorter term at a lower rate can save a large amount of interest and build equity faster. Enter a shorter new term to see the trade-off between the monthly payment and lifetime interest saved.
Does refinancing restart my mortgage?
A rate-and-term refinance replaces the old loan with a new one on a fresh term, so yes, the clock restarts. Choosing a new term equal to your remaining years avoids stretching the payoff date while still capturing a lower rate.
API — use this calculator from code
Call this calculator as a free JSON endpoint — no key required. Send the field values below as query parameters or JSON. Read the full API docs →
Endpoint
GET https://calculator.free/api/v1/refinance/curl
curl "https://calculator.free/api/v1/refinance/?balance=250000¤t_rate=6.5&years_left=25&new_rate=5.5&new_years=30&costs=4000"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/refinance/?" + new URLSearchParams({
"balance": "250000",
"current_rate": "6.5",
"years_left": "25",
"new_rate": "5.5",
"new_years": "30",
"costs": "4000"
}));
const data = await r.json();
console.log(data.results);Results are estimates for general guidance only, not financial, medical or tax advice.