Refinance

Refinance Calculator

Should you refinance? Compare your current loan to a new offer and see your monthly savings, break-even point, and lifetime cost in one chart.

How the refinance calculator works

Refinancing means replacing your existing mortgage with a new loan — usually to secure a lower interest rate, change the loan term, or access home equity. When you refinance, the new lender pays off your old mortgage and you begin making payments on the new one. The core question is always the same: do the long-term savings outweigh the upfront cost of getting the new loan?

The most important number in any refinance decision is the break-even point — the month at which your cumulative monthly savings finally exceed the closing costs you paid upfront. Until you pass that month, you are still in the red on the refinance. This calculator computes the break-even point automatically and charts your running savings over time so you can see exactly where the crossover happens.

Closing costs are often overlooked because they are rolled into the loan or paid at signing without much fanfare, but they typically run 2–5% of the loan balance. On a $300,000 mortgage that is $6,000–$15,000. Ignoring those costs leads borrowers to overestimate their savings — especially when they move or sell before recouping them.

The formula

The break-even calculation is straightforward division:

break-even months = closing costs ÷ monthly savings

Monthly savings is the difference between your current principal-and-interest payment and your new one. Each payment is derived from the standard amortization formula:

monthly payment = P × [r(1+r)^n] / [(1+r)^n − 1]

  P = loan balance
  r = monthly interest rate (annual rate ÷ 12)
  n = total number of monthly payments

To compare lifetime cost, the calculator sums all future interest payments on both the current loan and the refinanced loan, then subtracts one from the other. This gives you the true lifetime interest savings (or cost) of refinancing — which can look very different from the monthly savings figure, especially when you extend the term.

Worked example

Suppose you have a $300,000 balance at 7.5% with 25 years remaining. Your current monthly principal-and-interest payment is approximately $2,187.

A lender offers you 6.25% on a new 30-year loan with $4,500 in closing costs. Your new monthly payment would be roughly $1,847 — a monthly saving of about $340.

Break-even: $4,500 ÷ $340 ≈ 13 months. If you plan to stay in the home for several more years, the refinance pays off quickly. However, notice that you are resetting from a 25-year remaining term to a fresh 30-year loan, adding 5 extra years of payments. The total interest paid over the new loan life is around $365,000 versus roughly $283,000 remaining on the original loan — meaning the refinance actually costs more in total interest despite the lower rate and lower monthly payment. The calculator surfaces both numbers so you can weigh monthly cash flow relief against long-term cost.

When to use this calculator

Interest rates have dropped 0.5–1% or more below your current rate and you want to quantify the actual saving after closing costs.
Your credit score has improved significantly since origination and you believe you now qualify for a materially better rate.
Your ARM (adjustable-rate mortgage) is approaching its reset date and you want to lock in a fixed rate before the adjustment.
You want to shorten your term — for example, move from a 30-year to a 15-year mortgage to pay off the home faster and reduce total interest, even if the monthly payment rises.
You are considering a cash-out refinance to fund home improvements, consolidate debt, or cover a large expense, and you want to understand how the larger balance affects your payment and break-even.

Key concepts

Break-even point: The month at which your cumulative monthly savings equal the closing costs paid. Refinancing only makes financial sense if you plan to stay in the home past this point.
Closing costs: Fees paid to complete the refinance — including origination fees, appraisal, title insurance, and prepaid interest. They typically range from 2% to 5% of the loan balance and are either paid upfront or rolled into the new loan balance.
APR (Annual Percentage Rate): APR reflects the true annual cost of the loan by including fees and points alongside the interest rate. When comparing refinance offers, compare APRs rather than just the quoted interest rates — a lower rate with high fees can have a higher APR than a slightly higher rate with minimal fees.
Cash-out vs. rate-and-term refinance: A rate-and-term refinance only changes your interest rate and/or loan term — your balance stays roughly the same. A cash-out refinance replaces your mortgage with a larger loan, giving you the difference in cash. Cash-out refis generally carry slightly higher rates and increase both your balance and monthly payment.

Common mistakes

Ignoring closing costs. A lower rate feels like a guaranteed win, but if you sell or move within the break-even period you lose money on the refinance. Always model the break-even before committing.
Extending the term to lower the payment. Refinancing from 20 years remaining into a new 30-year loan can dramatically lower your monthly payment while dramatically increasing total interest paid — the total interest trap. Compare lifetime cost, not just the monthly figure.
Refinancing too frequently. Each refinance resets the break-even clock. Refinancing every two or three years — even to marginally lower rates — means you are perpetually paying closing costs and never fully recouping them.
Using cash-out funds for discretionary spending. Tapping home equity for vacations or consumer goods converts low-cost, tax-advantaged debt into funding for depreciating purchases and increases foreclosure risk if income falls.
Not comparing a HELOC to a cash-out refi. If you only need access to equity and your existing mortgage rate is competitive, a home equity line of credit may be cheaper than resetting your entire first mortgage at today's rates with new closing costs.

Frequently asked questions

When does refinancing make sense?

Refinancing generally makes sense when: (1) you can reduce your rate by at least 0.5–1%, (2) you plan to stay in the home long enough to pass the break-even point, and (3) your financial situation — credit score, income, equity — supports qualifying for the better rate. Even a modest rate reduction adds up over years; the key is ensuring the upfront cost is recoverable within your expected timeline.

What is a typical break-even period?

Most rate-and-term refinances break even in 18–36 months, though it can be shorter if you have very low closing costs or a large rate reduction. A cash-out refinance with higher closing costs can take 3–5 years to break even. Calculate yours with the actual numbers rather than relying on rules of thumb — the calculator does this instantly.

What is the difference between a cash-out and rate-and-term refinance?

A rate-and-term refinance simply replaces your existing mortgage at a new rate and/or term without significantly changing your balance. A cash-out refinance gives you a larger loan than your current balance — you receive the difference in cash. Cash-out refis typically carry a slightly higher rate, increase your loan balance and monthly payment, and restart amortization from scratch.

How much can I save with a 1% rate drop?

On a $300,000 mortgage, a 1% rate reduction saves roughly $150–$175 per month in principal-and-interest, depending on the remaining term. Over the full life of a 30-year loan that is more than $50,000 in total interest. However, if you extend the term when refinancing, total interest paid can still rise even with a lower rate — which is why the calculator shows both monthly savings and lifetime interest.

How does a mortgage refinance compare to a HELOC?

A refinance replaces your entire first mortgage. A HELOC (home equity line of credit) is a separate revolving credit line secured by your equity — your original mortgage stays untouched. If your current mortgage rate is already low, a HELOC lets you access equity without disrupting that rate. Refinancing makes more sense when rates have dropped enough to justify the closing costs across the whole balance.

How many times can I refinance my mortgage?

There is no legal limit on refinancing frequency. However, practical constraints apply: each refinance incurs closing costs and resets the amortization clock, so refinancing too often can cost more than it saves. Some lenders also impose a seasoning requirement — typically 6–12 months — before they will refinance a loan they recently originated.

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This tool is for educational purposes only and does not constitute financial advice. Consult a licensed mortgage professional before making refinance decisions.