Refinance Calculator

Written by Great Medico

Updated September 25, 2026 •3 min read

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Refinance Calculator turns the values on the form into a focused planning estimate. It compares an existing loan or mortgage with a new financing scenario using the rates, terms, balance, new-loan amount, or closing-cost fields shown and keeps the arithmetic visible enough to sanity-check.

What this calculator does

Refinance Calculator compares an existing loan or mortgage with a new financing scenario using the rates, terms, balance, new-loan amount, or closing-cost fields shown. The form asks for current loan balance, current annual rate, current remaining term, new annual rate, new loan term, and refinance closing costs. The result should therefore be read as a calculation from those displayed assumptions, not as live market, lender, tax, or government-program data unless the page explicitly supplies such a feed.

How to use it

Enter Current loan balance, Current annual rate, Current remaining term, New annual rate, New loan term, and Refinance closing costs. Keep monetary inputs in one currency; the currency selector formats results and does not convert exchange rates. Enter rates and percentages on the scale shown by the field label; do not silently switch between a decimal and a percent. Keep time values in the period shown on the form so a monthly figure is not accidentally entered as an annual one or vice versa. Before calculating, recheck Current loan balance, Current annual rate, Current remaining term against the source values you intend to model. If a default value is already filled in, confirm that it matches the scenario you actually want to test rather than assuming the preset is current or personally appropriate.

How the calculation works

Refinance comparisons use standard amortization to estimate old and new payments. Mortgage refinance adds closing costs to the refinanced balance in the payment comparison. Cash-out refinance estimates cash received as new loan amount − current mortgage balance − closing costs. This is the calculation method to use when checking the result from Refinance Calculator; values not represented by a visible input should not be inferred as part of the model.

Example

A $300,000 current balance at 7% with 25 years remaining is compared with a new 6% 30-year loan that also finances $5,000 of closing costs. The headline shows the modeled monthly payment difference, not the lifetime-interest difference.

How to interpret the result

A lower new monthly payment does not automatically mean a lower lifetime cost; extending the term can reduce payment while increasing total interest. Cash-out results also represent new debt secured by the asset. Keep the assumptions with the result so a later recalculation can be compared consistently.

Limitations and notes

Quotes can include points, lender credits, taxes, title costs, escrow changes, prepayment penalties, appraisal, cash-to-close rules, and rate-lock terms. Compare total cost and break-even horizon, not only monthly payment. Rounding and timing conventions can cause a real statement or account balance to differ slightly from the model.