Mortgage Comparison Calculator (USA)
Compare two fixed-rate mortgage options side-by-side. See monthly payments, total interest, payoff timelines, and the impact of extra principal — for both loans at once.
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PDF export includes extended amortization schedules for both options.
How to Use the Mortgage Comparison Calculator
You don’t need a financial advisor to figure out which mortgage wins. Follow these four steps and the calculator will compute a full side-by-side comparison — including total interest, monthly payment difference, payoff timelines, and two amortization schedules — in seconds.
Enter Option A — Your First Scenario
Input the home price, down payment, interest rate, and loan term for your first mortgage scenario. Add optional costs — property tax, homeowners insurance, HOA dues, and extra monthly payment — to make the comparison as accurate as possible. U.S. average rates are pre-filled so you can start immediately.
Enter Option B — Your Second Scenario
Option B can be anything: a different rate on the same loan, a shorter term, a larger down payment, a different home price, or a refinance offer. The home prices, loan amounts, and terms do not need to match. This flexibility makes it useful for rate shopping, term comparisons, and refinance analysis in a single tool.
Hit Compare and Read the Results
Click Compare Mortgages and review the highlighted winner — the option with lower total interest. The results panel shows monthly payment for each option, the exact dollar difference, total interest for each, and cumulative interest savings. Six summary cards give you a snapshot of every key metric in one view.
Download the PDF and Share With Your Lender
Download a two-page PDF report with both loan detail panels, the monthly payment comparison, summary cards, and complete amortization schedules for both options — colour-coded blue for Option A and amber for Option B. Share this with your lender, co-borrower, or financial advisor at your next meeting.
What This Calculator Computes
Most online mortgage calculators only show one loan at a time. This tool runs both scenarios simultaneously and builds a true financial comparison — with every cost that affects your real monthly obligation and lifetime interest cost.
Side-by-Side Loan Details Panel
Both options are displayed in a clean two-column layout showing home price, loan amount, interest rate, loan term, monthly P&I, total monthly cost, total interest paid, and adjusted payoff date — all in one view so nothing gets lost in a back-and-forth comparison.
Total Interest Winner & Savings Hero
The calculator automatically identifies which loan option saves more total interest and highlights it in the hero panel with the exact dollar savings figure. The interest savings and monthly payment difference are displayed prominently — not buried in a table — so the answer is immediately clear.
Extra Monthly Payment Modeling
Add an extra principal payment to either or both options. The calculator recomputes total interest and payoff months with the accelerated payoff applied — showing exactly how much time and money an extra $100, $200, or $500/month saves over the life of each loan.
Dual Amortization Schedules
Full month-by-month principal, interest, and remaining balance tables for both Option A and Option B — each on its own page in the PDF. Option A rows are highlighted in blue for first-month-of-year rows; Option B uses amber. Download the PDF to see both complete schedules side by side.
PMI Calculation for Conventional Loans
If your down payment is below 20% of the home price, the calculator automatically applies a monthly PMI estimate to the conventional loan. PMI raises your total monthly cost and is factored into the comparison — so both options reflect what you will actually pay each month, not just the P&I payment.
Two-Page PDF Comparison Report
Download a professionally formatted PDF with the full comparison on page 1 — loan details, monthly payment table, and six summary cards — and both amortization schedules on pages 2 and 3. Formatted to share directly with a lender, real estate agent, or co-borrower without requiring any additional tools.
Numbers Every U.S. Borrower Should Know Before Comparing Loans
How Different Borrowers Use This Calculator
The mortgage comparison is useful in dozens of situations — not just refinancing. Here’s how three common types of U.S. borrowers get the most out of it, and which comparison to set up first.
Buyers Choosing a Term
15-year vs. 30-yearYou’ve been pre-approved and are deciding whether to take the lower payment on a 30-year or absorb the higher payment on a 15-year and save dramatically on interest. The right answer depends on your budget cushion and long-term goals.
- Enter the same loan amount in both options, then adjust the term and rate
- Use 15-year rate as Option A (typically 0.5% lower) and 30-year as Option B
- Check the monthly payment difference — is it manageable for your budget?
- The interest savings figure is the true cost of choosing 30 years over 15
Homeowners Evaluating a Refinance
Current vs. new loanYou have an existing mortgage and received a refinance offer at a lower rate. You want to know if the monthly savings are worth the closing costs — and how long you need to stay to break even on the deal.
- Option A: current remaining balance, current rate, remaining term in years
- Option B: refinance payoff amount, new rate, new term (often 30-year reset)
- Divide total closing costs by the monthly savings shown to get break-even months
- Compare total interest — a longer term with a lower rate often costs more overall
Borrowers Testing Extra Payments
Accelerated payoffYou have a 30-year mortgage and want to know the exact dollar and time impact of paying an extra $200, $300, or $500 per month toward principal. The comparison makes this tangible — not theoretical.
- Option A: your current loan with $0 extra payment (baseline)
- Option B: same loan with your planned extra payment amount
- The interest savings figure is what the extra payment is worth over the full term
- Check the payoff date difference — that’s how many years sooner you’ll be mortgage-free
7 Ways to Get More From Your Mortgage Comparison
The numbers you put in determine the accuracy of the comparison. These tips help you set up both scenarios correctly so the output is meaningful — not misleading.
Always Compare Total Interest, Not Just Monthly Payment
A 30-year loan at 5.5% has a lower monthly payment than a 15-year at 6.0% — but costs roughly twice as much in total interest. Monthly payment tells you what’s affordable. Total interest tells you what the loan actually costs. Use both figures together, not either one alone.
Use the Real Rate You’ve Been Quoted, Not the Advertised Rate
Advertised mortgage rates often require excellent credit, large down payments, and specific loan sizes. Enter the rate from your actual pre-approval or rate sheet — not the headline rate you saw online. A 0.25% difference in the rate changes the comparison result by tens of thousands of dollars on a large loan.
Match the Loan Amount Correctly for Refinance Comparisons
When comparing a refinance, use your current unpaid principal balance — not your original loan amount. Your current balance is on your most recent mortgage statement. If your servicer charges a payoff penalty, add that to the new loan amount in Option B to get an accurate picture of the refinance cost.
Model the “Do Nothing” Case as Your Baseline
Set Option A as your current situation — your existing loan with no changes. Then model the proposed change in Option B. This gives you a true before/after comparison. The interest savings figure will then represent the real value of the decision you’re evaluating, not an abstract difference between two hypothetical loans.
Test Rate Sensitivity With the Slider
Mortgage rates change weekly. Use the rate slider to model the best and worst case within your expected range before locking. Moving from 6.5% to 7.0% on a $400,000 30-year loan costs an additional $122/month and $43,700 in total interest — knowing that in advance helps you decide whether to lock or float.
Factor In How Long You’ll Stay in the Home
If you plan to sell in 5–7 years, the total interest difference between a 15-year and 30-year loan matters much less than the monthly payment difference — because you won’t stay long enough to realize the full savings. Check both options’ amortization schedules at your expected exit year to compare remaining balances and cumulative interest paid at that point.
Download the PDF Before Your Lender Meeting
Lenders present numbers quickly and it can be difficult to keep track of competing scenarios in real time. Download the two-page PDF comparison report and bring it to your pre-approval or rate-lock meeting. Having your own calculated comparison on paper puts you in a stronger negotiating position and helps you ask sharper questions about any discrepancies.
Mortgage Comparison Calculator FAQ
Straight answers to the questions U.S. borrowers ask most when comparing two loan options.
Important disclaimer: All calculations provided by this tool are for educational and estimation purposes only and do not constitute financial, legal, or mortgage advice. Results assume standard fixed-rate amortization and may not reflect exact lender calculations, points, fees, or adjustments specific to your loan. PMI rates, property tax percentages, and insurance costs vary by lender, location, credit profile, and loan-to-value ratio. Always consult a licensed mortgage lender or loan officer and obtain a formal Loan Estimate before making any financial decisions. HomeExpertly is not a lender, broker, or financial advisor.