Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
New monthly payment
$1,458.93
Old monthly payment
$1,760.48
Monthly savings
$301.55
Break-even (months)
13
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How to use this
- 1Enter current balance ($).
- 2Enter current rate (%).
- 3Enter years left (years).
- 4Enter new rate (%).
- 5Enter new term (years).
- 6Enter closing costs ($).
- 7Read your new monthly payment on the right — it updates as you type.
- 8Hit Share to keep the scenario or send it to someone.
About this calculator
Estimate monthly savings and break-even months when refinancing your mortgage.
Worked example
Using the values the calculator loads with:
Inputs
- Current balance: 250000 $
- Current rate: 7.25 %
- Years left: 27 years
- New rate: 5.75 %
- New term: 30 years
- Closing costs: 4000 $
Results
- New monthly payment: $1,458.93
- Old monthly payment: $1,760.48
- Monthly savings: $301.55
- Break-even (months): 13.26
What each field means
Inputs
- Current balance ($)
- The current balance used in the calculation, measured in $. Starts at 250000 $ so you have a working example on load.
- Current rate (%)
- The current rate used in the calculation, measured in %. Starts at 7.25 % so you have a working example on load.
- Years left (years)
- The years left used in the calculation, measured in years. Starts at 27 years so you have a working example on load. Accepted range: 1–50 years.
- New rate (%)
- The new rate used in the calculation, measured in %. Starts at 5.75 % so you have a working example on load.
- New term (years)
- The new term used in the calculation, measured in years. Starts at 30 years so you have a working example on load. Accepted range: 1–50 years.
- Closing costs ($)
- The closing costs used in the calculation, measured in $. Starts at 4000 $ so you have a working example on load.
Results
- New monthly payment
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Old monthly payment
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Monthly savings
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Break-even (months)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the mortgage refinance calculator work?
Estimate monthly savings and break-even months when refinancing your mortgage.
What do I need to enter?
6 values: current balance, current rate, years left, new rate, new term, and closing costs. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the new monthly payment result mean?
It is returned as a money amount in US dollars and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Refinance Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/refinance
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/refinance" target="_blank" rel="noopener">Refinance Calculator — RevenueLab</a> (2026).</p>
Source: [Refinance Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/refinance) (2026).