How to use the refinance calculator
- Current loan balance — how much you still owe on your mortgage today.
- Current APR — the annual interest rate on your existing loan.
- Current monthly payment — your principal-and-interest payment only (leave out property taxes and homeowners insurance).
- New APR — the interest rate you have been quoted for the refinance.
- New term — the length of the new loan in years, such as 15 or 30.
- Closing costs — lender fees, appraisal, title and other costs to refinance. Use 0 for a no-cost estimate.
The results update the moment you change a number, so you can try different rates and terms to see what makes the most sense.
What the numbers mean
Your new monthly payment is calculated by amortizing your current balance over the new term at the new rate. The monthly savings is simply your old payment minus the new one. The break-even point tells you how many months of those savings it takes to recover your closing costs — if you plan to keep the home longer than that, the refinance generally pays off.
The estimated lifetime savings compares the interest you would still pay on your current loan against the total interest on the new loan, then subtracts your closing costs. A positive number means you save money over the life of the loan; a negative number is common when a refinance stretches the payoff date far into the future, even if your monthly payment drops.
When refinancing makes sense
- Rates have fallen: a meaningfully lower APR is the most common reason to refinance.
- You will stay put: if you will own the home well past the break-even point, the closing costs are worth it.
- You want a shorter term: moving from a 30-year to a 15-year loan can slash total interest, even if the monthly payment rises.
- You need lower payments now: extending the term lowers the monthly cost, though it can raise lifetime interest.
Always weigh the monthly savings against the lifetime savings — a lower payment is not always a cheaper loan.
Frequently asked questions
How is the new monthly payment calculated?
It uses the standard amortization formula on your current balance, the new monthly interest rate, and the number of months in the new term.
What is the break-even point?
It is how many months it takes for your monthly savings to add up to your closing costs. After that, the refinance is ahead.
Why is my lifetime savings negative?
Extending your loan term can mean more total interest even when the monthly payment drops. The lifetime figure captures that trade-off after closing costs.
Is my data uploaded?
No — everything is calculated in your browser and nothing is sent anywhere.
This tool is for general information only and is not financial advice. Confirm all figures with your lender.
Related: Loan & Mortgage Calculator, Compound Interest Calculator, Simple Interest Calculator.