Mortgage Comparison Calculator
Compare two mortgage options side-by-side — monthly payment, total interest, lifetime cost, and more. Find which loan saves you more money.
AMortgage A
Purchase price or appraised value
20.0% of home price — no PMI required
Only charged when down payment < 20%
BMortgage B
20.0% of home price — no PMI required
Quick Tips
- A 20% down payment eliminates PMI and can save thousands over the loan term.
- Even a 0.5% rate difference translates to tens of thousands in total interest on a large loan.
- Compare total cost — not just monthly payment — to find the truly cheaper mortgage.
Summary
Lower Monthly
Mortgage A
saves $659/mo
Less Interest
Mortgage B
$264,671 less
Lower Total Cost
Mortgage B
saves $348,671
Side-by-Side Comparison
| Metric | A | B |
|---|---|---|
| Loan Amount | $320,000 | $320,000 |
| Interest Rate | 7.00% | 6.50% |
| Term | 30 yrs | 15 yrs |
| Monthly P&I | $2,128.97 | $2,787.54 |
| Monthly Tax | $366.67 | $366.67 |
| Monthly Insurance | $100.00 | $100.00 |
| Monthly PMI | $0.00 | $0.00 |
| Total Monthly | $2,595.63 | $3,254.21 |
| Total Interest | $446,428 | $181,758 |
| Total Cost (lifetime) | $1,014,428 | $665,758 |
Green values indicate the lower-cost option for that metric.
Monthly Payment Breakdown
Estimate Only
Results are estimates based on fixed-rate amortization. ARM payments will change after the introductory period. Consult a licensed mortgage professional for official loan quotes.
What Is a Mortgage Comparison?
A mortgage comparison is the process of evaluating two or more home loan options against each other to determine which offers the best value for your specific financial situation. A mortgage is almost always the largest financial commitment most people will make in their lifetime, yet millions of borrowers accept the first offer they receive without running a side-by-side analysis. Understanding how different loan terms, interest rates, down payment amounts, and fees interact can save you tens of thousands of dollars over the life of the loan.
Every mortgage has four cost components: the principal and interest (P&I) payment, property taxes, homeowner's insurance, and — when the down payment is less than 20% — private mortgage insurance (PMI). Lenders quote the P&I payment prominently because it is the portion they control, but your true monthly obligation includes all four components. This mortgage comparison calculator computes every component for both loans simultaneously so you can make a fully informed decision.
How to Compare Two Mortgages
The standard formula for a fixed-rate monthly P&I payment is derived from the present value of an annuity:
Mortgage Payment Formula
M = P × [r(1+r)^n] / [(1+r)^n − 1]
M — monthly principal & interest payment
P — loan amount (home price minus down payment)
r — monthly interest rate = annual rate ÷ 12
n — total payments = term in years × 12
To compare two mortgages, compute M for each loan, then add the shared costs: monthly property tax (annual rate × home price ÷ 12), monthly insurance (annual premium ÷ 12), and monthly PMI (annual PMI rate × loan amount ÷ 12) when applicable. Add all four components to arrive at the total monthly payment. Multiply the P&I payment by n to get total P&I paid; subtracting the original loan amount gives total interest. Add the down payment and all taxes, insurance, and PMI payments to get the true lifetime cost of each mortgage.
Worked Examples
These examples illustrate the most common mortgage comparison scenarios borrowers face.
Example 1: 15-Year vs. 30-Year Fixed
Loan: $320,000 | Down payment: $80,000 | 30yr @ 7.0% vs. 15yr @ 6.5%
- 30-year monthly P&I: $2,129 | Total interest: $446,473
- 15-year monthly P&I: $2,788 | Total interest: $181,838
- Choosing the 15-year saves $264,635 in interest at the cost of $659/month more.
Example 2: Down Payment Impact & PMI
Home price: $350,000 | 30yr @ 7.0% | 5% down ($17,500) vs. 20% down ($70,000)
- 5% down: loan $332,500, PMI ~$221/mo, total monthly ~$2,630
- 20% down: loan $280,000, no PMI, total monthly ~$2,028
- The larger down payment saves $602/month and eliminates PMI entirely, though it requires $52,500 more upfront.
Example 3: Rate Shopping (Same Term)
Loan: $400,000 | 30-year | 6.75% vs. 7.25%
- 6.75%: monthly P&I $2,594 | total interest $533,767
- 7.25%: monthly P&I $2,728 | total interest $581,957
- A 0.5% rate reduction saves $134/month and $48,190 in total interest — a powerful argument for shopping multiple lenders.
Mortgage Scenario Comparison Table
Common mortgage configurations on a $400,000 home with 20% down ($80,000), no PMI, $150/mo insurance, 1.1% property tax.
| Loan Type | Rate | Term | Monthly P&I | Total Interest | Total Cost |
|---|---|---|---|---|---|
| 30-yr Fixed | 7.00% | 30 yr | $2,129 | $446,473 | $875,673 |
| 20-yr Fixed | 6.75% | 20 yr | $2,422 | $261,216 | $661,416 |
| 15-yr Fixed | 6.50% | 15 yr | $2,788 | $181,838 | $541,838 |
| 10-yr Fixed | 6.25% | 10 yr | $3,573 | $108,701 | $508,901 |
The 15-year mortgage strikes the best balance between monthly payment and total interest savings for most borrowers with stable income. The 30-year provides maximum flexibility but costs the most overall.
When to Use This Mortgage Comparison Calculator
This calculator is most valuable in the following situations:
- Comparing lender quotes: When you have received Loan Estimates from two or more lenders, enter both quotes to see which is truly cheaper over your expected hold period.
- Choosing a loan term: If you are deciding between a 15-year and 30-year mortgage, the calculator instantly shows the monthly payment difference and lifetime interest savings.
- Evaluating a refinance: Enter your current mortgage as Loan A and the refinance offer as Loan B to see whether the lower rate justifies the closing costs and extended timeline.
- Modeling down payment scenarios: Compare two down payment amounts to decide whether putting extra cash toward your down payment beats investing it elsewhere.
- First-time homebuyer research: Before speaking with a lender, use this tool to understand how different interest rate and term combinations affect your budget.
Tips for Accurate Mortgage Comparisons
- Use the same home price for both loans. If you are comparing two financing options for the same property, enter identical home prices and taxes so the comparison isolates the loan terms.
- Include PMI in your analysis. PMI can add $100–$300 or more per month on a $300,000–$400,000 loan. Enter an accurate PMI rate (ask your lender) to avoid understating your true monthly cost.
- Check your property tax rate. Property tax rates vary widely by state and county — from under 0.5% in Hawaii to over 2% in New Jersey. Look up your specific county rate for accurate results.
- Factor in your time horizon. If you plan to sell or refinance within 7 years, a 30-year mortgage may cost less in total payments than a 15-year, even though the latter saves more interest if held to term.
- Get at least three lender quotes. Studies by the Consumer Financial Protection Bureau (CFPB) show that borrowers who get at least three quotes save an average of $1,500 over the life of their loan compared to those who get one quote — and some save much more.
Frequently Asked Questions
About This Calculator
Free mortgage comparison calculator. Compare two mortgage loans side-by-side — monthly payments, total interest, break-even point, and lifetime costs instantly.
Frequently Asked Questions
How accurate is the Mortgage Comparison Calculator for my local market?
This calculator uses national averages and standard real estate formulas. Local market conditions — including property taxes, insurance rates, HOA fees, rental demand, and appreciation rates — can vary significantly by city and neighborhood. For the most accurate results, input your actual local data rather than relying on defaults. Consult a local real estate agent or appraiser for market-specific figures. Property taxes alone can range from 0.3% (Hawaii) to 2.5% (New Jersey) of assessed value, dramatically affecting calculations.
What assumptions does the Mortgage Comparison Calculator make that I should be aware of?
Key assumptions include: stable property appreciation rates (typically 3-4% default), consistent rental income without extended vacancies, standard maintenance costs (1-2% of property value annually), and current 2025 interest rates. The calculator does not account for major unexpected expenses (foundation repairs, roof replacement), changes in local zoning or regulations, economic downturns affecting property values, or tenant-related issues (evictions, damage). Conservative investors should add 10-20% buffer to expense estimates and use pessimistic scenarios for critical investment decisions.
Should I use this calculator before making a real estate investment decision?
This calculator is an excellent starting point for evaluating potential investments, but should be one of several tools in your decision-making process. Also consider: hiring a professional property inspector ($300-$500), reviewing comparable sales (comps) from the past 6 months, analyzing local rental market data (Zillow, Rentometer), consulting with a real estate attorney for legal considerations, and speaking with local property managers about realistic expense ratios. Never make a six-figure investment decision based solely on calculator outputs — they model best-case scenarios that rarely match reality perfectly.
How do interest rate changes affect the results of this calculation?
Interest rates significantly impact real estate calculations. A 1% rate increase on a $400,000 30-year mortgage increases monthly payments by approximately $240 and total interest paid by $86,000 over the loan term. For investment properties, higher rates reduce cash flow and may push DSCR below lender requirements. When rates rise, property values typically adjust downward to maintain investor returns. Run the calculator at current rates plus 1-2% to stress-test your investment against potential rate increases before committing.
What tax benefits should I consider alongside these calculations?
Real estate offers several tax advantages not fully captured in basic calculators: mortgage interest deduction (up to $750,000 loan), property tax deduction (up to $10,000 SALT cap), depreciation of rental property over 27.5 years (significant paper loss reducing taxable income), 1031 exchange to defer capital gains, pass-through deduction (20% of qualified business income for rental property owners), and cost segregation studies for accelerated depreciation. These benefits can significantly improve after-tax returns. Consult a tax professional familiar with real estate investing for your specific situation.
Alex specializes in personal finance modeling with experience in investment analysis and tax optimization. He ensures every financial calculator follows current IRS guidelines and industry-standard formulas.
- CFA Level II Candidate
- B.S. in Finance, University of Michigan
- 8 years in financial planning tools