Mortgage Recast Calculator

Compare current and recast principal-and-interest payments, remaining balance, and modeled interest after a one-time principal reduction.

Current principal balance

Interest rate (%)

Remaining term (months)

Lump-sum principal curtailment

—Current modeled P&I

—Recast modeled P&I

—Monthly payment reduction

—Balance after curtailment

—Modeled remaining-interest difference if the rate and maturity stay unchanged.

A recast is not the same as simply making an extra principal payment. It requires the servicer to re-amortize the lower balance; eligibility, minimum curtailment, fees, and loan-type rules vary.

How to use the Mortgage Recast Calculator

Enter the current principal, fixed interest rate, remaining months, and proposed lump-sum principal curtailment. The tool re-amortizes the reduced balance over the same remaining term and compares modeled payments.

Recast versus extra principal

Making a principal payment by itself does not guarantee a lower required monthly payment. A recast requires servicer re-amortization and may have eligibility, minimum-payment, timing, fee, or loan-type rules.