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Mortgage loan comparison calculator
Compare two fixed-rate mortgage options for a purchase or refinance. Enter each loan's balance, rate, term, and upfront costs to see the monthly payment difference, total interest, payoff timing, and simple cost break-even.
The balance path
Annual amortization, side by side
Both options are paid off after 30 years. The cumulative column shows how much less interest Option B has accrued.
Swipe sideways to compare every column.
| Year | Option A | Option B | Cumulative interest difference | ||||
|---|---|---|---|---|---|---|---|
| Principal | Interest | Ending balance | Principal | Interest | Ending balance | ||
Read the result correctly
Compare mortgage payments and total costs
Monthly P&IEscrows are intentionally excluded so the financing difference stays visible.
Interest over timeThe schedule starts from the balances and remaining terms you enter; interest already paid is not included.
Upfront costsEnter cash-paid costs only. They affect total modeled cost and the simple payment break-even, not amortization.
A worked example
How to calculate refinance break-even
Hypothetical assumptionsA current $400,000 balance at 6.50% with 25 years remaining; a new $400,000 loan at 6.00% for 25 years; and $5,000 in new cash-paid closing costs. Both loans are fixed and fully amortizing, with no cash out or financed fees. These are educational figures, not rate quotes.
Monthly P&I savingsThe existing loan's modeled principal and interest is $2,700.83 per month. The new loan's is $2,577.21: a reduction of about $123.62 per month.
Simple break-even$5,000 ÷ $123.62 ≈ 40.45 months. The cumulative principal-and-interest payment reduction first covers those cash-paid costs in month 41. This estimate excludes taxes, insurance, HOA dues, mortgage insurance, tax effects, and the time value of money.
Your expected timelineCompare that recovery period with how long you expect to keep the new loan. Then compare interest, costs, and the balance still owed at the same future date; simple payment break-even alone does not measure your full financial benefit.
Make the comparison useful
Mortgage comparison questions, answered
Which term should I enter for my current loan?Use the years remaining, together with today's unpaid balance. This calculator accepts whole years; ask Fred for a month-specific comparison if your payoff date falls between them. Past interest and original closing costs are already paid and do not belong in a comparison of future costs.
Does a lower payment mean a cheaper refinance?A longer new term can lower your payment while increasing total interest. Compare the remaining payoff schedule with the proposed schedule. The CFPB's refinance guide illustrates this tradeoff.
Where do closing costs go?Enter new cash-paid costs in the upfront-cost field. Add financed fees to the new loan balance and uncheck the matching-balance option; do not enter the same fees twice. Financed costs accrue interest. The Federal Reserve's refinancing guide explains financed fees and cost recovery.
What should I compare next?Bring the result to your refinance review or purchase planning conversation. If a seller offers a temporary payment subsidy, use the 2-1 buydown calculator to see its payment steps and funding requirement.