Mortgage Loan Comparison Calculator
Compare two mortgage loan offers side by side. See total interest, monthly payment, and true cost differences. Find the better deal before you sign.
Reviewed for accuracy by Marcus Webb and the Blueprint Dynamics editorial team (last updated July 2026). Our calculators use primary-source formulas and are cross-checked against IRS publications, Fannie Mae guidelines, and Federal Reserve data. Learn more about our methodology.
Source: Federal Reserve, Freddie Mac, Bankrate national averages. Rates are approximate ranges for borrowers with good credit (700+). Actual rates depend on your credit score, loan-to-value ratio, and lender.
Loan Comparison Tool
Compare two loan scenarios side by side and find the better deal.
Loan A
Loan B
Better dealLoan B saves you $240,581 over Loan A in total cost.
Comparing loans: the numbers that matter
When evaluating two or more loan offers, the relevant comparison metrics are: Monthly payment (affordability), Total interest paid over the full term (total cost), APR including fees (true rate comparison), and Payoff date. A lower monthly payment doesn't mean a cheaper loan — a 7-year loan at 7% has lower monthly payments than a 5-year loan at 6%, but costs significantly more in total interest because of the extended repayment period. The calculator shows all four metrics simultaneously so you can make a true apples-to-apples comparison.
How small rate differences compound over time
On a $30,000 loan: a 1% rate difference (8% vs. 7%) over 5 years costs $814 more in total interest — meaningful but not dramatic. Over 30 years (like a mortgage), 1% on $300,000 costs approximately $63,000 more in total interest. This is why shopping mortgage rates aggressively is far more important than shopping personal loan rates — the same rate difference applies to a longer term and a larger balance, producing much larger absolute differences.
Fixed vs. variable rate loans
Fixed-rate loans: payment and interest rate never change — complete certainty over the repayment period. Best when rates are low (you lock in) or when predictability is important (budgeting, long terms). Variable-rate loans: rate typically starts lower than fixed but adjusts periodically based on a benchmark (Prime Rate, SOFR). Best when rates are high and expected to fall, when the loan will be repaid quickly, or when you can tolerate payment variability. For most personal loans and mortgages at standard terms, fixed rates are preferable because the payment certainty and protection against rising rates is worth the slightly higher initial rate.
When a longer term is the wrong choice
Lenders often frame longer-term options in terms of lower monthly payments, which can obscure the true cost. On a $15,000 auto loan: 36 months at 6% → payment $456, total interest $1,424. 60 months at 6% → payment $290, total interest $2,396. 72 months at 7% → payment $256, total interest $3,432. The 72-month option has the lowest payment but costs 2.4x as much in total interest as the 36-month. Unless the lower payment is genuinely necessary for cash flow, a shorter term is almost always the better financial decision for the borrower.