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
Break-even point
20.1
months
Monthly payment saving
$324
New monthly payment (P&I)
$1,898
Current monthly payment (P&I)
$2,222
Lifetime interest saved after costs
$30,106
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter loan balance to refinance ($).
- 2Enter current interest rate (%).
- 3Enter years left on current loan (years).
- 4Enter new interest rate (%).
- 5Enter new loan term (years).
- 6Enter closing costs (incl. points) ($).
- 7Read your break-even point on the right — it updates as you type.
- 8Hit Share to keep the scenario or send it to someone.
About this calculator
Refinancing only makes sense if you stay in the home past the break-even point — the month where cumulative payment savings finally exceed the closing costs you paid to get the lower rate. This calculator compares your current loan against a new loan on the remaining balance, accounts for the fact that a fresh 30-year term restarts amortization (lower payment, more total interest), and reports both the simple break-even in months and the lifetime interest difference. Enter the balance you would refinance, your current rate and remaining term, the new rate and term, and total closing costs including origination, appraisal, title, and any points. A common rule of thumb says refinance when you can cut the rate by 0.75-1.00 points, but the honest test is personal: if your break-even lands past the date you expect to sell or refinance again, the deal loses money no matter how much lower the rate looks.
Worked example
Using the values the calculator loads with:
Inputs
- Loan balance to refinance: 320000 $
- Current interest rate: 7.1 %
- Years left on current loan: 27 years
- New interest rate: 5.9 %
- New loan term: 30 years
- Closing costs (incl. points): 6500 $
Results
- Break-even point: 20.1
- Monthly payment saving: $324
- New monthly payment (P&I): $1,898
- Current monthly payment (P&I): $2,222
- Lifetime interest saved after costs: $30,106
What each field means
Inputs
- Loan balance to refinance ($)
- The loan balance to refinance used in the calculation, measured in $. Starts at 320000 $ so you have a working example on load. Accepted range: 10000–3000000 $.
- Current interest rate (%)
- The current interest rate used in the calculation, measured in %. Starts at 7.1 % so you have a working example on load. Accepted range: 0.5–15 %.
- Years left on current loan (years)
- The years left on current loan used in the calculation, measured in years. Starts at 27 years so you have a working example on load. Accepted range: 1–40 years.
- New interest rate (%)
- The new interest rate used in the calculation, measured in %. Starts at 5.9 % so you have a working example on load. Accepted range: 0.5–15 %.
- New loan term (years)
- The new loan term used in the calculation, measured in years. Starts at 30 years so you have a working example on load. Accepted range: 5–40 years.
- Closing costs (incl. points) ($)
- The closing costs (incl. points) used in the calculation, measured in $. Starts at 6500 $ so you have a working example on load. Accepted range: 0–60000 $.
Results
- Break-even point
- months
- Monthly payment saving
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- New monthly payment (P&I)
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Current monthly payment (P&I)
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Lifetime interest saved after costs
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why can my payment drop but lifetime interest rise?
Restarting a 30-year term on a loan you had already paid down for several years stretches the balance over more months. The payment falls, yet total interest can exceed what you would have paid on the old schedule. Compare the lifetime figure, not just the payment.
Should I roll closing costs into the loan?
It preserves cash but adds to the balance and to interest. The break-even math here treats costs as paid up front; if you finance them, add the amount to the balance instead and set costs to zero.
What about a no-cost refinance?
Lenders cover costs by raising your rate. Set closing costs to zero and enter the higher quoted rate — the comparison stays valid and often shows the no-cost option winning for shorter holding periods.
Does this include taxes and insurance?
No. It compares principal and interest only, which is where a refinance changes your payment. Escrow amounts stay roughly the same either way.
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). Mortgage Refinance Break-Even Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/refinance-break-even-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/refinance-break-even-calculator" target="_blank" rel="noopener">Mortgage Refinance Break-Even Calculator — RevenueLab</a> (2026).</p>
Source: [Mortgage Refinance Break-Even Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/refinance-break-even-calculator) (2026).