A lump sum with 25 years remaining
If a $320,000 balance at 6.5% has 25 years left, a $40,000 principal payment followed by an approved recast lowers the estimated principal-and-interest payment while keeping the same rate and payoff period.
RecastPlan • US mortgage planning estimate
RMortgage Recast Calculator: Payment After Lump Sum
Estimate a new mortgage payment after a lump-sum principal payment and lender recast.
Using this tool
Lower the balance without restarting the loan
Enter the current balance, unchanged interest rate, remaining term, planned principal payment and estimated lender fee. RecastPlan re-amortizes the lower balance across the original remaining payoff period.
Reading the output
A recast changes payment, not the rate
Re-amortizing the lower principal
New balance = current balance minus lump sum. The standard fixed-rate payment formula is applied to both balances using the same monthly rate and remaining number of payments.
Ask the servicer before paying
- Ask the servicer whether the loan is eligible before sending a lump sum for recasting.
- Confirm the minimum principal payment and recast fee.
- Escrowed taxes and insurance are separate and may keep the total monthly bill from falling by the same amount.
Before relying on the result
Eligibility, fees and escrow
Is a mortgage recast the same as refinancing?
No. A recast generally keeps the existing loan, rate and payoff date, while refinancing replaces the loan and can change its rate, term and closing costs.
Will every mortgage servicer approve a recast?
No. Eligibility, minimum principal payments, timing and fees vary by loan and servicer.