Mortgage Recast calculator

Mortgage Recast Calculator

Compare three scenarios side by side: your original mortgage, a mortgage recast (lower payment, same payoff date), and a lump sum payment without recasting (same payment, earlier payoff). See exactly how much interest each option saves so you can choose what's best for your situation.

3-scenario side-by-side · interest savings · payoff change · lump sum impact

Loan Details

Original Loan Amount ($)

Annual Interest Rate (%)

Loan Term (years)

Loan Start Date

Lump Sum Payment

Lump Sum Amount ($)

applied to principal

Recast Fee ($)

typical: $150–$500

Applied In

month of lump sum payment

Side-by-Side Comparison

Enter your loan details and lump sum above, then click Calculate to see the three-scenario comparison.

* For informational purposes only. Results are estimates based on standard amortization formulas and may vary from your actual loan terms. Recast availability, minimum lump sum requirements, and fees vary by lender and loan type. Consult your mortgage servicer before making any financial decisions.

What Is a Mortgage Recast?

A mortgage recast (also called loan recasting or re-amortization) is a lender service that recalculates your monthly payment based on a new, lower principal balance after you make a substantial lump sum payment. Your loan term and interest rate stay exactly the same, only your required monthly payment changes. The lender rebuilds the amortization schedule from the remaining balance and remaining months, producing a lower mandatory monthly payment for the rest of the loan.

Recasting is specifically designed to provide payment relief rather than accelerated payoff. This is the essential distinction between a recast and simply making an extra principal payment. When you make an extra payment without recasting, your required monthly payment stays the same and the loan pays off earlier. When you recast, your monthly payment drops and the loan pays off on its original schedule. The calculator above lets you compare both outcomes side by side.

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Recasting slows payoff compared to keeping the original payment. If you apply a $30,000 lump sum, recast your loan, and then pay the lower required payment, you will pay more lifetime interest than if you had applied the same $30,000 and kept making the original higher payment. The recast saves interest versus the original loan (because the principal is lower), but Scenario 3 in the calculator above always produces the greatest interest savings when you keep the higher payment.

Mortgage Recast vs. Extra Payment vs. Refinancing

	Mortgage Recast	Extra Payment (No Recast)	Refinance
Monthly payment	Decreases	Stays the same	Changes (depends on new rate/term)
Loan term	Same original term	Shorter (pays off early)	New term
Interest rate	Unchanged	Unchanged	New rate (could be higher or lower)
Interest savings	Moderate (lower balance)	Maximum (lower balance + faster payoff)	Variable (depends on rate difference)
Closing costs / fee	$150–$500 recast fee	None	2–5% of loan amount
Credit check required	No	No	Yes (hard inquiry)
Qualification required	Minimal	None	Full underwriting
Best for	Lowering payment without changing rate or term	Maximizing total interest savings	Getting a lower rate on the full balance

How to Use This Mortgage Recast Calculator

Enter your original loan details. Use the original loan amount from when you first took out the mortgage (not your current balance). Enter the rate, term, and start date, the calculator uses these to compute your current balance and remaining term automatically.

Enter your lump sum and recast fee. The lump sum is the amount you plan to apply toward principal. The recast fee (typically $150–$500) is charged by the lender to process the recast. Enter the actual fee your servicer charges, or leave the default $250 as a reasonable estimate.

Review all three scenarios. The calculator shows your original loan (baseline), the recast (lower payment, same payoff date), and the lump sum without recasting (same payment, earlier payoff). The third scenario always saves more lifetime interest, but requires keeping the higher payment. Use the comparison to decide which outcome fits your financial goals.

Mortgage Recast Requirements

Recasting is available on most conventional mortgages but comes with several lender-specific requirements. Before requesting a recast, verify the following:

Loan type: Conventional (Fannie Mae / Freddie Mac) loans generally allow recasting. FHA loans, VA loans, and USDA loans typically fall outside recasting eligibility. Some jumbo loan servicers permit it.
Minimum lump sum: Most servicers require a minimum principal payment of $5,000 to $10,000 before approving a recast request. Some set the minimum as high as $25,000. Confirm with your servicer before sending funds.
Payment history: Many servicers require your loan to be current with no missed or late payments in the past 12 months.
Account age: Lenders often require the loan to be at least 12 months old before allowing a recast.
Recast fee: Expect to pay $150–$500 directly to your servicer to process the re-amortization.
Principal-only application: Confirm with your servicer that the lump sum payment is applied to principal before requesting the recast, some servicers apply extra payments as future installments by default.

When a Mortgage Recast Makes Sense

After a Home Sale or Windfall

The most common scenario: you sell your previous home and use the equity as a lump sum against your current mortgage. Recasting lets you reduce the ongoing payment burden without giving up your current interest rate, which matters if your original rate is below current market rates.

Low Interest Rate Lock-In

If you locked in a mortgage rate below current market rates (e.g., 3–4% in 2020–2021), refinancing would replace that rate with a higher current rate, costing more interest on the full balance. Recasting preserves the original rate while giving you payment relief from the lump sum you apply. This situation makes a recast clearly superior to a refinance for most borrowers.

Payment Relief Without Qualification

Refinancing requires full income verification, a credit check, appraisal, and closing costs of 2–5% of the loan amount. Recasting requires none of that. If your income has changed, your credit has taken a hit, or you simply want to avoid the cost and hassle of refinancing, a recast provides payment relief through a simple servicer request.

When a Recast Makes Less Sense

If maximizing total interest savings is your primary goal, keeping your current monthly payment and applying the lump sum to principal (without recasting) always wins. You save more interest by eliminating principal faster while maintaining the same payment. The tradeoff is a higher required monthly commitment. Use Scenario 3 in the calculator above to see the interest advantage clearly.

Frequently Asked Questions

What is a mortgage recast? −

A mortgage recast is a service offered by most conventional loan servicers that recalculates your monthly payment after you make a large lump sum principal payment. After the payment is applied, the lender rebuilds your amortization schedule based on the new lower balance and the same remaining term and interest rate. Your monthly payment drops because the principal is lower, but your payoff date and interest rate stay the same. Recasting costs a flat fee ($150–$500) and requires no credit check or income verification.

Is a mortgage recast worth it? −

A recast is worth it when your primary goal is a lower monthly payment and you want to preserve your current interest rate. It makes particular sense when your existing rate is well below current market rates, making refinancing unattractive. It saves more interest than doing nothing with the lump sum, though it saves less than keeping your original payment and applying the lump sum as an extra principal payment. The calculator above shows all three outcomes side by side so you can decide based on your actual numbers.

What is the difference between a recast and a refinance? −

A recast changes only your monthly payment by re-amortizing your remaining balance at the same rate and term. A refinance replaces your entire loan with a new loan at a new rate, new term, and typically requires closing costs of 2–5% of the loan amount plus a full credit and income qualification. A recast costs $150–$500 and requires no qualification. The right choice depends on current rates: if rates have risen since your original loan, recasting preserves your lower rate while a refinance would increase it. If rates have fallen significantly, refinancing on the full balance may produce greater total savings despite closing costs.

How much can I save by recasting my mortgage? −

Savings depend on the lump sum applied, your current interest rate, and your remaining loan term. On a $400,000 loan at 6.75% with 25 years remaining, applying a $50,000 lump sum and recasting saves roughly $94,000 in lifetime interest compared to making no change. The same $50,000 applied without a recast (keeping the original payment) saves approximately $106,000, about $12,000 more than the recast scenario. The difference grows at higher interest rates and longer remaining terms. Use the calculator above with your specific numbers to see the exact savings.

Which loans qualify for recasting? −

Conventional loans backed by Fannie Mae and Freddie Mac typically qualify for recasting. Most jumbo loans can be recast, though requirements vary by servicer. FHA loans, VA loans, and USDA loans generally cannot be recast under their program guidelines. The loan must usually be current (no missed payments), at least 12 months old, and the lump sum must meet a minimum threshold (commonly $5,000–$10,000, though some servicers require $25,000 or more). Contact your loan servicer directly to confirm whether your specific loan is eligible and what their requirements are.

Should I pay extra toward my mortgage or request a recast? −

If maximizing interest savings is your goal, apply the lump sum as an extra principal payment and keep making your original monthly payment. This always saves more interest than recasting, because you eliminate principal faster while maintaining the same payment pace. If reducing your monthly cash flow commitment is the priority, perhaps your income has changed or you want to free up cash for other goals, a recast is the better choice. It provides meaningful payment relief while still saving interest compared to making no extra payment. The calculator above shows the exact dollar difference between both approaches for your specific loan.

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Recast vs. Extra Payment

Example · $400K loan · 6.75% · 25yr remaining Lump sum applied $50,000 No change (baseline) Pay original amount Recast (Scenario 2) ~$94K interest saved Lump sum only (Scenario 3) ~$106K saved + pays off ~4 years early Recast monthly savings ~$350/mo lower payment Best for interest Scenario 3 (always)

Recast Requirements

Eligible loans Conventional (Fannie/Freddie), most jumbo Excluded loans FHA, VA, USDA (typically) Minimum lump sum $5,000–$25,000 (varies by servicer) Recast fee $150–$500 (flat) Credit check None required Loan age Usually 12+ months Payment status Must be current

When Recasting Wins

Rate below market Preserves low rate (refinance would raise it) Need payment relief Lowers required monthly outflow Windfall / home sale Apply equity without refinancing Avoid qualification No income check, no appraisal Low closing cost $150–$500 vs 2–5% for refi