Calculate monthly savings and break-even timeline for refinancing a loan.
Imagine you have a mortgage balance of $350,000 with 25 years remaining on a 30-year term. Your current interest rate is 6.8%. You receive an offer from a lender to refinance into a new 30-year mortgage at 5.5% interest rate. The new rate is lower, but the refinancing process costs $6,000 in closing fees (appraisal, title, lender fees). Is it worth refinancing? To answer this, you must calculate the monthly payment savings and determine how many months it will take to "break even" on the closing costs. Our Refinance Calculator is built to perform this comparison so you can see if refinancing makes sense.
Refinancing a mortgage replaces your current loan with a new loan under different terms. Homeowners refinance to lower their interest rate, shorten their term (e.g., from 30 years to 15 years), or cash out equity. When I was building this refinance tool, my goal was to highlight the impact of the break-even period. Lenders often focus on the "monthly savings" without emphasizing the upfront fees. If your monthly payment drops by $150 but you pay $6,000 in fees, you must stay in the home for at least 40 months just to break even.
The core concept behind our tool is the comparative amortization model. The calculator takes your current loan parameters and compares them against the new loan parameters. It tracks the monthly principal and interest (P&I) payments for both loans, calculates the monthly savings, and divides the closing costs by the savings to find the break-even month. It also calculates the total lifetime cost of both loans, showing you the true interest savings after factoring in the extended term, conforming with standards set by the Federal Reserve board.
Our tool runs through a precise order of calculations. First, it calculates the monthly payment (P&I) of your current mortgage based on the current balance, interest rate, and remaining term. Second, it calculates the monthly payment of the proposed mortgage based on the refinance loan amount (which can include the closing costs rolled in), new interest rate, and new term. Third, it subtracts the new payment from the current payment to find the monthly savings. Finally, it divides the closing costs by the monthly savings to find the break-even point in months.
Note: If you roll your closing costs into the new loan balance, you will pay interest on those fees for the next 30 years, which increases your financed principal and reduces your monthly savings.
The current monthly payment M_curr is computed as:
M_curr = Current Balance * [r_curr(1+r_curr)^n_curr] / [(1+r_curr)^n_curr - 1]Where r_curr is the current monthly rate and n_curr is the remaining term in months.
The new monthly payment M_new is computed as:
M_new = Refinance Balance * [r_new(1+r_new)^n_new] / [(1+r_new)^n_new - 1]Where r_new is the new monthly rate and n_new is the new term in months.
The monthly savings S is:
S = M_curr - M_newThe break-even period in months N_be is:
N_be = Closing Costs / SLet's run a worked example. Suppose you have a current balance of $300,000 with 20 years (240 months) remaining at 6.5% interest rate. The proposed loan is a new 20-year mortgage at 5.5% interest rate, with closing costs of $5,000. We calculate the savings as follows:
Current Loan:
P = $300,000, r = 6.5 / 12 / 100 = 0.005417, n = 240 months
M_curr ≈ $2,236.40
Proposed Loan:
P_new = $300,000, r_new = 5.5 / 12 / 100 = 0.004583, n_new = 240 months
M_new ≈ $2,063.90
Monthly Savings:
S = $2,236.40 - $2,063.90 = $172.50
Break-Even Period:
N_be = $5,000 / $172.50 ≈ 28.98 months (29 months)In this scenario, it will take 29 months (about 2.4 years) to break even on the closing costs. If you plan to live in the property for 3 years or more, the refinance is beneficial. The total interest savings over the 20-year term will be: ($172.50 * 240) - $5,000 = $36,400, making this a smart financial choice.
Rate-and-Term Refinance Evaluation: A homeowner in Denver has a $400,000 loan at 7.0% with 28 years left. The payment is $2,710/mo. A bank offers a 5.8% rate on a new 30-year loan with $6,000 closing fees. The calculator shows the new payment drops to $2,347/mo (saving $363/mo). The break-even period is 17 months. Since they plan to stay in the home for 5 years, refinancing is a clear win.
Shortening the Loan Term: A couple in Portland has 22 years left on a 6.5% mortgage with a $250,000 balance. They want to know if they can refinance into a 15-year term at 5.0% without raising their payment too much. The calculator shows their current payment is $1,920/mo, and the new 15-year payment is $1,977/mo. By paying just $57/mo more, they cut 7 years off their debt and save over $82,000 in interest.
Comparing Closing Cost Quotes: A buyer gets two refinance quotes on a $300,000 loan: Quote A offers 5.5% interest with $4,000 in closing fees. Quote B offers 5.25% interest with $7,000 in closing fees. The calculator shows that Quote B saves an extra $48/mo compared to Quote A, but costs $3,000 more upfront. The break-even on the extra fee is 62 months. Since they might move in 4 years, they choose Quote A.
Cash-Out Refinance Analysis: An owner wants to borrow $50,000 from their home equity for remodeling. They compare a cash-out refinance of their entire $200,000 mortgage at 6.0% against taking a separate Home Equity Loan (HELOAN) at 8.5%. The calculator shows that refinancing the entire balance at a higher rate than their current 4.0% mortgage is very expensive. They choose the HELOAN instead to preserve their low rate.
ARM to Fixed-Rate Conversion: A homeowner with a 5/1 Adjustable Rate Mortgage (ARM) sees their rate adjusting from 3.5% to 6.5%. They use the calculator to evaluate converting to a 30-year fixed loan at 5.8%. While the fixed payment is higher than their initial ARM rate, the calculator shows that it protect them from future rate adjustments, providing budget certainty.
Know your break-even period before signing. The break-even period is the most important metric. If you plan to move before reaching the break-even point, you will lose money. I always tell my clients that if their break-even period is longer than 36 months, they should shop around for lower closing costs or a slightly higher rate with lender credits.
Do not roll closing costs into the loan balance blindly. Adding closing fees to your loan balance increases your interest payment. For a $6,000 fee rolled into a 6.0% loan, you will pay $36/mo for 30 years, totaling $12,960. If you have the cash, pay the closing costs upfront to maximize your monthly savings.
Avoid extending your loan term if possible. If you have paid on a 30-year mortgage for 8 years, you have 22 years remaining. Refinancing into a new 30-year mortgage drops your payment but extends your term by 8 years. This can increase the total interest you pay. Consider refinancing into a 20-year or 15-year mortgage to keep your repayment timeline on track.
Combine with the APR Calculator to evaluate points. Lenders offer lower rates if you pay "discount points" upfront. A discount point costs 1% of the loan value and lowers the rate by 0.25%. Use our APR Calculator to verify if the cost of the points is justified by the rate reduction before running this refinance tool.
Shop at least three different lenders. Refinance rates and closing costs vary widely. A local credit union may offer lower fees, while an online lender might offer a lower interest rate. Getting loan estimates from multiple lenders gives you leverage to negotiate lower fees and secure the best deal.
The break-even logic compares monthly payments: Savings = M_curr - M_new. The break-even month is computed as ClosingCosts / Savings. Lifetime interest comparison matches the remaining current interest against the new amortized interest plus fees.
The code is executed entirely in your browser. The comparison of current and new amortization models, including interest calculations over 360 periods, runs in less than 2 milliseconds, providing instant feedback as you adjust the sliders.
All inputs, including current balances and closing costs, remain inside your browser. No data is stored, shared, or sent to external servers, providing a private environment for your budget calculations.
Compatible with Chrome, Safari, Firefox, and Chromium Edge. The layout is optimized to be responsive on mobile viewports as small as 320px, making it handy to use while negotiating at the bank.
| Metric | This Tool | Lender Refinance Quote | Standard Amortization Sheet |
|---|---|---|---|
| Break-Even Output | Specific Month Count | Often Omitted | Not Supported |
| Interest Extension Cost | Included in Total | Often Hidden | Not Applicable |
| Data Security | 100% Client-side | Server-side Portal | 100% Client-side |
| Tenure Options | 1 to 30 Years | Fixed (15 or 30 Years) | Years Only |
Closing costs are fees charged by the lender and third parties to process your new mortgage. They typically range from 2% to 5% of the loan value. Common fees include lender origination charges ($1,000-$1,500), home appraisals ($400-$600), title insurance ($1,000-$2,000), and government recording fees ($100-$200).
A common rule of thumb is to refinance if you can lower your interest rate by 1.0% or more. However, a rate reduction of 0.5% can be beneficial if your loan balance is large or if you plan to stay in the home for a long time. The best metric to look at is the break-even period, which should be shorter than your planned stay in the home.
A no-closing-cost refinance is a mortgage where the lender pays the closing costs in exchange for a slightly higher interest rate. While you do not pay cash upfront, the higher rate increases your monthly payment and total interest cost. Use this calculator to see if the higher rate is cheaper than paying the closing costs in cash.
Yes, you can refinance with bad credit, but you will pay a higher interest rate and higher fees. If you have an FHA or VA loan, you may qualify for a "streamline refinance" which does not require credit checks or income verification. For conventional loans, improving your credit score before refinancing will secure you a much better rate.
Refinancing will cause a temporary drop in your credit score of a few points. This is because the lender will perform a "hard inquiry" to check your credit history, and your old mortgage account will be closed and replaced with a new one. However, as you make timely payments on your new mortgage, your score will quickly recover.
Mortgage Calculator: To calculate your base monthly payment including property taxes and home insurance, use our Mortgage Calculator. It provides a complete housing payment outline.
APR Calculator: Use the APR Calculator to convert a lender's nominal interest rate quote and fee structure into the true APR before running this refinance comparison.
EMI Calculator: For standard loans in India and other markets using equated monthly installments, check the EMI Calculator for localized rate calculations.