Comparison table
| Metric | Offer A | Offer B | Difference |
|---|---|---|---|
| Loan amount | $360,000 | $360,000 | $0 |
| Monthly P&I | $2,335 | $3,087 | $752 |
| Monthly tax | $431 | $431 | $0 |
| Monthly insurance | $150 | $150 | $0 |
| Monthly PMI | $0 | $0 | $0 |
| Total monthly | $2,916 | $3,668 | $752 |
| Cash to close | $98,500 | $98,500 | $0 |
| Total interest | $480,583 | $195,610 | $284,973 |
| Lifetime cost | $1,148,333 | $758,735 | $389,598 |
What Is a Mortgage Comparison Calculator?
A mortgage comparison calculator helps you compare two loan offers using the same assumptions. A lender may advertise a lower rate, a lower fee, a lender credit, or a shorter term. Each choice affects payment, upfront cash, interest, and long-term cost differently. This calculator keeps those tradeoffs visible on one screen.
The tool is especially useful when you have two Loan Estimates, when you are comparing a 15-year mortgage with a 30-year mortgage, or when you are deciding whether discount points are worth the extra cash at closing. It also helps show how PMI changes the monthly payment when one option has a smaller down payment.
How to Calculate Mortgage Comparison
The principal and interest payment uses the standard fixed-rate mortgage formula:
After calculating principal and interest, the calculator adds estimated property tax, homeowners insurance, PMI when loan-to-value is above 80%, and monthly HOA dues. Cash to close includes the down payment, closing costs, discount points, and lender credits. Lifetime cost adds upfront cash plus the monthly estimated costs over the selected term.
Worked Examples
Example 1: 30-year vs 15-year
A 30-year mortgage usually has the lower monthly payment because the same balance is spread over more months. A 15-year mortgage often has a higher payment but much lower total interest. The comparison table helps decide whether monthly cash flow or long-term cost matters more.
Example 2: Low rate with points vs higher rate with credits
A lower rate may require discount points, which increases upfront cash. A higher rate may come with lender credits, which lowers cash due now. If the monthly savings from the lower rate recover the points cost before you sell or refinance, the lower-rate offer can win. If not, the credit-heavy offer may be better.
When to Use This Calculator
Use this calculator before choosing a lender, locking a rate, buying points, or deciding how much to put down. It is not a substitute for a formal Loan Estimate, but it helps you know which questions to ask. When two offers look similar, compare both cash to close and lifetime cost instead of focusing only on the interest rate.
Frequently Asked Questions
How does a mortgage comparison calculator work?
A mortgage comparison calculator estimates two loan offers with the same payment formula and then compares monthly payment, cash to close, total interest, PMI, and lifetime cost. It helps separate short-term affordability from long-term cost.
What should I compare between mortgage offers?
Compare interest rate, APR, loan term, points, lender credits, closing costs, PMI, taxes, insurance, HOA dues, cash to close, and total interest. A lower rate is not always cheaper if it requires high points or fees.
Why can the lower monthly payment cost more over time?
A longer term or lower upfront cash option can reduce the monthly payment but increase total interest. A 30-year mortgage usually has a lower monthly payment than a 15-year mortgage, but it often costs much more in lifetime interest.
How do discount points affect a mortgage comparison?
Discount points increase upfront cash in exchange for a lower interest rate. They can be worth it if the monthly savings recover the points cost before you sell, refinance, or pay off the loan.
How do lender credits affect the comparison?
Lender credits reduce cash due at closing but may come with a higher rate. They can help with short-term cash flow, but the higher payment can cost more if you keep the mortgage for a long time.