How to Use This Calculator
- 1
Enter Loan A details
Input the principal amount, annual interest rate, and term in years for the first loan option.
- 2
Enter Loan B details
Input the principal amount, annual interest rate, and term in years for the second loan option.
- 3
Review your results and insights
Examine the Better Deal by Total Cost, monthly payments for each loan, total interest for each, and the monthly payment difference. The insights panel shows interest cost per dollar borrowed, the monthly payment trade-off, and a break-even analysis. Scroll down for the balance paydown chart and year-by-year comparison table.
Example Calculation
A homebuyer compares two $350,000 loan options: Loan A at 6.5% over 30 years and Loan B at 5.9% over 15 years.
Loan A Amount ($)
350,000
Loan A Interest Rate (%)
6.5
Loan A Term (years)
30
Loan B Amount ($)
350,000
Loan B Interest Rate (%)
5.9
Loan B Term (years)
15
Results
Better Deal by Total Cost
Loan B
Loan A Monthly Payment
$2,212.24
Loan B Monthly Payment
$2,934.62
Loan A Total Interest
$446,405.71
Loan B Total Interest
$178,232.18
Monthly Payment Difference
$722.38
Tips
Focus on Total Cost, Not Just Monthly Payment
While Loan A (30-year, 6.5%) has a lower $2,212/mo payment, Loan B (15-year, 5.9%) saves $268,174 in total cost. Always compare total interest and overall repayment — the cheapest monthly payment is not always the best deal.
Evaluate the Interest Cost Multiplier
Loan A charges $1.28 in interest per $1 borrowed, while Loan B charges only $0.51 per $1. This means Loan A's total cost is 2.28x the original loan, while Loan B's is 1.51x — a dramatic difference over the loan's life.
Consider Opportunity Cost of Higher Payments
Loan B requires $722/mo more than Loan A. If you invested that difference at 7% annually instead, you'd accumulate significant wealth over 15 years. Weigh the guaranteed interest savings against potential investment returns based on your risk tolerance.
Comparing Home Loan Options: Rates, Terms, and Total Costs
The Home Loan Comparison Calculator evaluates two mortgage options side by side, analyzing monthly payments, total interest, and overall cost.
For two $350,000 loans — Loan A at 6.5% over 30 years ($2,212.24/mo) and Loan B at 5.9% over 15 years ($2,934.62/mo) — Loan B saves $268,174 in total cost despite the $722 higher monthly payment.
Understanding Mortgage Terms and Their Financial Impact
The choices you make about interest rates and loan duration have profound long-term consequences.
A 30-year mortgage offers lower monthly payments but accumulates far more interest.
The 15-year option demands higher monthly payments but can save hundreds of thousands in interest.
On $350,000 at 6.5%, you pay $446,406 in interest over 30 years — more than the original loan amount.
At 5.9% over 15 years, interest totals just $178,232.
The Amortization Formula for Loan Comparisons
Both loans use the standard amortization formula to calculate fixed monthly payments:
monthly payment = (P × r × (1 + r)^n) / ((1 + r)^n − 1)
Where P = principal, r = monthly rate (annual rate / 12), n = total payments (years × 12).
total interest = (monthly payment × n) − P
total cost = monthly payment × n
The calculator applies this formula to each loan and compares the results directly.
Worked Example: Two $350,000 Mortgage Scenarios
Comparing two $350,000 home loan options:
- Loan A: 6.5% rate, 30-year term
- Loan B: 5.9% rate, 15-year term
- Loan A Monthly Payment: r = 6.5%/12 = 0.005417, n = 360 → $2,212.24/mo
- Loan A Total Interest: ($2,212.24 × 360) − $350,000 = $446,406
- Loan A Total Cost: $796,406
- Loan B Monthly Payment: r = 5.9%/12 = 0.004917, n = 180 → $2,934.62/mo
- Loan B Total Interest: ($2,934.62 × 180) − $350,000 = $178,232
- Loan B Total Cost: $528,232
- Total Savings: $796,406 − $528,232 = $268,174
- Monthly Payment Difference: $2,934.62 − $2,212.24 = $722.38
Loan B saves $268,174 in total cost while paying off 15 years sooner.
The trade-off is a $722/mo higher payment.
Fixed-Rate vs. Alternative Mortgage Structures
This calculator compares fixed-rate, fully amortizing loans.
Other structures exist: interest-only mortgages have lower initial payments but no principal reduction, and ARMs start with a lower rate that adjusts over time.
When comparing, ensure you are evaluating similar loan types for an accurate assessment.
A fixed-rate comparison eliminates rate-change uncertainty and provides a clear apples-to-apples analysis.
The Role of Loan-to-Value (LTV) in Mortgage Pricing
LTV ratio — your loan amount relative to the home's value — significantly affects the interest rate you receive.
An 80% LTV (20% down payment) typically qualifies for the best rates, potentially 0.25-0.5% lower than a 95% LTV loan.
Loans above 80% LTV also require Private Mortgage Insurance (PMI), adding $50-$200/month to costs.
Factor LTV-driven rate differences into your loan comparison for a complete picture.
Frequently Asked Questions
What factors should I compare between home loans?
Compare interest rates, APR (which includes fees), loan terms, monthly payments, total interest paid, closing costs, and whether the rate is fixed or adjustable. Also consider lender reputation, customer service, and any special programs for first-time buyers.
Is a lower interest rate always the better deal?
Not necessarily. A loan with a lower rate but higher closing costs may cost more overall than a slightly higher rate with lower fees. Compare the APR, which factors in all costs, and calculate the break-even point to determine which loan saves more over your expected ownership period.
Should I compare 15-year vs. 30-year mortgages?
A 15-year mortgage has higher monthly payments but lower interest rates and far less total interest. A $350,000 loan at 6% costs about $754,000 total over 30 years versus $533,000 over 15 years. Choose based on your budget and long-term financial goals.