Money
Mortgage Recast Calculator
Enter your current loan balance, interest rate, remaining term, and the lump-sum principal payment. The calculator returns the new monthly payment, monthly savings, and lifetime interest savings.
Principal remaining on the mortgage today. · e.g. 280,000
Annual rate on the existing loan; a recast keeps your rate. · e.g. 6.5
Years left on the original amortization. · e.g. 27
Most servicers require a minimum (often $5,000 to $10,000) and charge a small recast fee. · e.g. 30,000
What is a recast?
A mortgage recast (re-amortization) drops a lump-sum payment against the principal and re-amortizes the loan over the same remaining term and at the same rate. Monthly payment goes down; payoff date does not change. Unlike a refinance, recasts do not require an appraisal, closing costs, or a new loan.
Not lending or financial advice. Confirm with your loan servicer whether recasting is allowed, the minimum lump sum, the recast fee, and any waiting period.
New monthly P&I
$1,638.89
Was $1,835.55 · saves $196.67 per month
P&I (principal and interest) only. Taxes, insurance, PMI, and HOA dues are unchanged by a recast. Servicer fees and minimum lump-sum requirements vary; estimate ignores them.
Examples
$280,000 · 6.5% · 27 yrs · +$30,000 recast
Was $1,890/mo, now $1,688 · saves $202/mo
$200,000 · 7% · 28 yrs · +$25,000 recast
Was $1,338, now $1,171 · saves $167/mo
$400,000 · 5% · 25 yrs · +$50,000 recast
Was $2,338, now $2,046 · saves $292/mo
$150,000 · 4% · 20 yrs · +$20,000 recast
Was $909, now $788 · saves $121/mo
How it works
A recast re-amortizes your loan over the same remaining term at the same rate. The math is identical to the original mortgage payment formula, just with the new (smaller) principal balance.
New balance · balance − lump_sum
Payment · P × r × (1+r)^n / ((1+r)^n − 1)
Total interest · payment × months − principal
P = principal, r = monthly rate (annual rate / 12 / 100), n = remaining months on the original schedule.
Related money calculators
- Mortgage calculator for the full monthly payment with taxes, insurance, PMI, and HOA.
- Mortgage refinance calculator for comparing a new loan at today's rate vs the current loan.
- Loan calculator for the general amortization math behind any installment loan.
- All money calculators.
Disclaimer. Lending estimate only. Servicer recast policies, minimum lump-sum amounts, fees, and eligibility (FHA, VA, USDA loans typically cannot be recast) vary. Confirm with your loan servicer before sending money. Not legal, lending, or financial advice.
Frequently asked questions
A recast (re-amortization) is when you apply a large lump-sum payment to your mortgage principal and the servicer re-runs the amortization on the remaining balance over the same remaining term, at the same rate. Your monthly payment drops; your payoff date stays the same.
A refinance replaces your existing loan with a new loan, usually with a new rate, new term, an appraisal, and closing costs. A recast keeps your loan, rate, and payoff date; you only pay a small servicer fee (often $150 to $500) and the lump-sum principal payment.
Most servicers require a minimum lump-sum principal payment, commonly $5,000 to $10,000. Some have a higher floor or a minimum percentage of the loan balance. The recast fee is a flat charge, not a percent of the loan. Check your loan agreement or call your servicer.
No. Most conventional (Fannie Mae, Freddie Mac) and jumbo loans allow recasting, but FHA, VA, and USDA loans typically do not. Some servicers limit recasts to one per loan or require a waiting period after origination. Always confirm before sending the lump sum.
Both reduce total interest. Extra principal payments keep your minimum monthly payment the same and shorten the payoff date. A recast lowers your minimum monthly payment but does not change the payoff date. Recasting is useful if you want lower required cash flow each month, for example after a windfall or home sale.
No. The rate on a recast stays the same as your current loan. If your current rate is much higher than today's market, a refinance (which gives you a new rate) usually saves more money than a recast, even after closing costs.
Monthly savings depend on the lump sum, the rate, and the remaining term. Lifetime interest savings are larger early in the loan when more of each payment is interest. The calculator shows both numbers based on the inputs you provide.
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