Mortgage Recast Calculator
A recast (a one-time payment that lowers your monthly bill without restarting the loan) is the quietest tool in the mortgage toolbox. You make a lump-sum payment toward principal and the servicer re-amortizes the remaining balance over the original term — same rate, same maturity date, lower monthly payment. No refinance, no closing costs, no credit pull. Most servicers charge a $150–$500 admin fee and require a minimum lump-sum ($5k–$25k is typical).
What you still owe before the lump-sum payment.
Stays the same after a recast — only the payment is recalculated.
How long until your scheduled payoff. A recast keeps this number the same.
Cash you apply to principal before the recast. Most servicers require a $5k–$25k minimum.
One-time admin fee. Typical: $150–$500. Some servicers waive it.
New payment $1,813 vs $2,149 today. $58,800 less interest over the remaining term.
$336 / mo lower P&I (principal and interest)
- New principal
- $270,000
- Interest paid (recast)
- $317,517
- Interest saved
- $58,800
- New monthly P&I
- $1,813
- Today's monthly P&I
- $2,149
- Net interest saved
- $58,550
- Recast fee break-even
- 1 mo
Free during pilot
How a recast actually works
After you apply a lump-sum payment to principal, the servicer re-amortizes the new (lower) balance over the remaining term at the same rate. The maturity date doesn't move. The new monthly principal-and-interest payment is computed with the standard amortization formula:
P × r / (1 − (1 + r)^−n)
where P is the new principal (balance minus lump-sum), r is the monthly rate (annual ÷ 12), and n is the number of months remaining. That's all this calculator does.
Recast vs. refinance vs. extra principal
- Recast. Same rate, same term, lower payment. Cheap ($150–$500), no credit pull, no closing costs. Best when you can't beat your current rate.
- Refinance. New loan, often new rate and new term. Closing costs of $3k–$8k, weeks of paperwork. Worth it when current rates are at least ~0.75% lower than your existing rate.
- Extra principal without recast. Same rate, same payment, shorter term. The interest savings is similar to a recast, but your monthly cash flow doesn't change. Use the mortgage payoff calculator for that path.
When a recast is the right tool
- You have a windfall — a bonus, an inheritance, equity from a sold property — and want lower fixed monthly outflow.
- Your current rate is lower than what you'd get refinancing today.
- You don't want to extend the term or restart the amortization clock.
What this calculator deliberately excludes
- Loan-program rules. FHA, VA, and USDA loans generally cannot be recast. Conforming conventional loans usually can. Always confirm with the servicer holding the loan.
- Escrow. A recast lowers your P&I, but escrow (tax, insurance, PMI (private mortgage insurance)) is unchanged. The full PITI (principal, interest, taxes, insurance) drop is exactly the P&I difference shown above.
- Servicer processing time. Most recasts post 30–60 days after the lump-sum hits principal. Until the new schedule is in effect, you still owe the old payment.
Frequently asked questions
What is a mortgage recast?
A recast is a one-time lump-sum payment toward principal, after which your servicer re-amortizes the lower balance over the original remaining term at the same rate. The maturity date does not move and the rate does not change — only the monthly principal-and-interest payment drops. There is no refinance, no closing costs, and no credit pull.
Is a recast cheaper than a refinance?
Usually, yes. Most servicers charge a $150–$500 admin fee for a recast versus $3,000–$8,000 in refinance closing costs, with no credit pull and no new term. A recast keeps your existing rate, so it is the better tool when you cannot beat your current rate; a refinance generally only pays off when current rates are roughly 0.75% or more below yours.
Which loans can be recast?
Conforming conventional loans (Fannie/Freddie) usually can, provided you are current on payments and meet the servicer's minimum lump-sum (typically $5,000–$25,000). FHA, VA, USDA, and most jumbo loans generally cannot be recast. Confirm eligibility, fee, and processing time with the servicer holding your loan before sending funds.
Does a recast lower my entire monthly payment?
It lowers only the principal-and-interest portion. Escrow items — property tax, insurance, and any PMI — are unchanged, so the total payment drop equals the P&I difference shown above. Most recasts post 30–60 days after the lump sum is applied; until then you still owe the old payment.
Related calculators
Estimates only — not a recast quote. Servicer rules vary: most require the loan be conforming (Fannie/Freddie) and current on payments, charge a $150–$500 fee, and require a $5k–$25k minimum lump-sum. FHA, VA, USDA, and most jumbo loans cannot be recast. Confirm eligibility, fee, and processing time with your servicer before sending funds. Methodology last reviewed: May 26, 2026.