Overview
The RefinanceUSA calculator answers one question: "Is refinancing my mortgage worth it — and which lender offer is best?" It does this by comparing your existing mortgage against one or more new lender offers, factoring in closing costs, and calculating how much you actually save over time. You can use it to evaluate any refinancing goal — switching to a fixed rate mortgage, removing mortgage insurance, accessing equity in your home, or simply lowering your monthly mortgage payment.
The calculator has two input sections and produces a detailed side-by-side comparison for each offer, including the full principal and interest breakdown, estimated closing costs, break-even point, and net savings over the life of the mortgage loan. This guide walks you through every field, explains what numbers to use, and shows you how to interpret the results.
Quick start: Have your most recent mortgage statement handy. It contains every number you need for Section 1.
Step 1 — Enter Your Current Mortgage Details
This section describes your existing loan. All four fields are required. You can find these numbers on your monthly mortgage statement or your original loan documents.
Field 1
Original Loan Amount
The total amount you borrowed when you first took out the mortgage — not the amount you owe today.
Example: $400,000
Field 2
Current Balance ($)
The outstanding principal you still owe on your loan today. Check your latest mortgage statement for the exact figure.
Example: $320,000
Field 3
Current Interest Rate (%)
Your existing mortgage's annual interest rate (not APR). Found on your statement or original loan documents.
Example: 6.75
Field 4
Remaining Term
How much time is left on your loan. Click Months to enter a single total (e.g. 276), or switch to Years & Months to enter them separately — the calculator combines them automatically.
23 yr 4 mo = 280 months
Common mistake: Don't enter the original loan amount in the Current Balance field. These are different numbers. The current balance is always lower than the original loan amount (unless you've done a cash-out refinance).
Where to find your remaining term: Your mortgage statement often lists the number of payments remaining directly. If it shows years, use the Years & Months toggle — no mental math needed.
Step 2 — Add Lender Offers
This section is where the calculator becomes powerful. You can enter multiple lender offers at once and compare them all side-by-side in the results. Start with at least two or three real quotes from different lenders for the most useful comparison.
Field 1
Bank / Lender Name
An optional label for the offer. Leave blank and the calculator will automatically label it "Bank #1", "Bank #2", etc.
Example: Chase, Wells Fargo, Local CU
Field 2
New Rate (%)
The interest rate offered by the lender for your new loan. Use the note rate — not the APR. Enter as a decimal percentage.
Example: 5.99
Field 3
Term (Years)
The length of the new loan in years. Common options are 10, 15, 20, and 30 years. Shorter terms mean higher monthly payments but much less total interest paid. Try the same rate with different terms to see the trade-off.
Example: 30 — or try 15 to compare the accelerated payoff
Adding more lenders: Click "＋ Add Lender" to add another row. There is no limit to how many offers you can compare. Click the ✕ button on any row to remove it.
Pro tip: Enter the same lender twice — once with a 30-year term and once with a 15-year term. This shows you exactly how much interest you save by choosing the shorter term, and whether the higher monthly payment is manageable.
Step 3 — Calculate & Compare
Once you have filled in your current mortgage details and at least one lender offer, click the "Calculate & Compare →" button. The calculator will instantly produce a full analysis for every offer you entered.
To start over, click "Reset" — this clears all fields and restores the two default lender rows.
Rate must be greater than 0: The only required fields on the lender rows are the interest rate and term. If you leave the lender name blank, the calculator will name it automatically — but the rate and term must be filled in.
Step 4 — Reading Your Results
For each lender offer, the calculator shows a detailed breakdown. Here is what every figure means:
New Monthly Payment
Your estimated monthly principal + interest payment under the new loan. Does not include taxes or insurance (escrow).
Monthly Savings
The difference between your current monthly payment and the new one. Positive means your payment goes down; negative means it increases (common when shortening the term).
Closing Costs (Est.)
Estimated upfront fees using national averages: 1% origination, $500 appraisal, 0.5% title insurance, $125 recording, $800 underwriting.
Break-Even Point
The number of months until your cumulative monthly savings repay the closing costs. If you plan to move before this point, refinancing likely isn't worth it.
Total Interest — Current
Total interest you will pay on your existing loan if you make no changes and pay it off on schedule.
Total Interest — New Loan
Total interest you will pay on the new refinanced loan over its full term.
Net Savings
The real bottom-line number: total interest saved minus closing costs. This is how much refinancing actually puts back in your pocket.
Verdict
A clear ✅ / ⚠️ / ❌ recommendation based on whether the net savings are positive within your remaining loan term.
At the bottom of the results, the Overall Recommendation card identifies the single best offer from among all the ones you entered and summarizes the key numbers in plain English.
Focus on Net Savings and Break-Even, not just monthly savings. A lower monthly payment that costs more in total interest over 30 years is not always a good deal. Use both figures together to make the best decision.
Tips for Getting the Most Accurate Results
Use your exact current balance
Even a small difference in the current balance changes the monthly savings calculation. Pull the exact payoff balance from your latest mortgage statement, not a rounded estimate.
Get real quotes before using the calculator
The calculator is most useful when you enter actual rates from real lenders — not hypothetical numbers. Spend 20 minutes getting Loan Estimates from 3–5 lenders, then plug those numbers in to compare them objectively.
Use the note rate, not the APR
Lenders advertise two rates: the note rate (used to calculate your payment) and the APR (which includes fees). Enter the note rate in the calculator. Use the APR separately to compare the true all-in cost between lenders.
Compare the same term across lenders
To do a fair rate comparison, make sure all lender rows use the same loan term. Mixing a 15-year and a 30-year offer in the same comparison is misleading — the lower monthly payment of the 30-year option does not mean it is cheaper overall.
Factor in how long you plan to stay
Pay close attention to the break-even point. If you plan to sell your home in 3 years and the break-even is 48 months, refinancing will actually cost you money — even if the rate is lower.
Try multiple scenarios
Run the calculator a few times with different inputs. What happens if you shorten to a 20-year term instead of 30? What if you pay one discount point for a 0.25% rate reduction? The calculator makes these "what-if" analyses instant and free.
Ready to Run the Numbers?
Open the free calculator, enter your mortgage details, and find out in seconds whether refinancing makes sense for you.
Open the Calculator →
Informational purposes only. Results produced by RefinanceUSA are estimates based on the inputs you provide and simplified calculation models. They do not constitute financial, legal, or mortgage advice. Actual rates, fees, and terms will vary by lender and your financial profile. Always consult a licensed mortgage professional before making refinancing decisions. RefinanceUSA is not a mortgage lender, broker, or financial institution.