Mortgage Recast Calculator
See your new monthly payment after a mortgage recast — enter your balance, a lump-sum principal payment, rate and remaining term to find the lower payment and your monthly savings.
Estimate only, not financial advice. Recasting rules, fees and minimum lump sums vary by lender; this tool re-amortizes the remaining balance at the same rate and term. Confirm details with your servicer.
How a mortgage recast works
When you recast a mortgage, you make a large one-time payment toward the principal and your lender re-amortizes the remaining balance over the same remaining term at the same interest rate. The result is a lower monthly payment — your rate and payoff date don’t change, but you owe less, so the principal-and-interest payment shrinks. This calculator computes the new payment with the standard amortization formula and shows your monthly saving.
Recast vs refinance vs paying ahead
A recast usually costs a small flat fee and keeps your current rate, which makes it attractive when you already have a good rate and a chunk of cash. Refinancing replaces the loan entirely (and your rate), with full closing costs. If your goal is to clear the loan sooner rather than lower the payment, see the pay off mortgage early calculator instead, or model the whole payment on the mortgage calculator.
Frequently asked questions
What is a mortgage recast?
A recast (or re-amortization) is when you make a large lump-sum payment toward your principal and the lender recalculates your monthly payment over the remaining term at the same interest rate. Your rate and payoff date stay the same, but the monthly payment drops because the balance is smaller.
How much will a recast lower my payment?
It depends on the lump sum and your remaining balance. For example, paying $50,000 toward a $300,000 balance at 6.5% with 25 years left lowers the principal-and-interest payment by roughly $340 a month. Enter your own numbers above to see the new payment.
Is recasting better than refinancing?
They solve different problems. Recasting keeps your existing rate and just lowers the payment after a lump sum, usually for a small fee and no credit check. Refinancing replaces the loan to change the rate or term, with full closing costs. If you have cash and a good rate already, recasting is often cheaper.