Mortgage Recast Calculator
A mortgage recast lowers your monthly payment by re-amortizing the remaining balance after a lump-sum principal payment, keeping your original rate and term. Enter your balance, lump sum, remaining years and recast fee above. On a $320,000 balance with 25 years left at an illustrative 6% rate, a $50,000 recast drops the payment by roughly $322 per month.
Your loan today
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down $0 from $0 a month
- New balance
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- Term after recast
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- Interest saved, after the fee
- $0
- Payment stays at
- $0.00
- Paid off early by
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- Interest saved
- $0
- Recasting costs you
- $0
A recast buys lower payments; prepaying the same amount buys a shorter loan and more interest saved. Neither is wrong — they answer different questions.
How Recasting Works
When you recast, you hand your servicer a lump sum — often $5,000 or more, depending on their minimum — and they recalculate your monthly payment based on the reduced balance over the remaining term. Your interest rate does not change. Your maturity date does not change. Only the required payment drops, because the principal the lender amortizes is now smaller.
The servicer charges a one-time recast fee, which varies by company. You enter that fee in the calculator so the net benefit is clear. Unlike a refinance, recasting does not require a credit check, an appraisal, or new closing costs. The paperwork is minimal, and the process usually takes a few weeks. This makes it attractive for borrowers who receive a windfall — a bonus, inheritance or proceeds from selling another property — and want immediate payment relief without touching their rate.
Recast vs Prepayment: Key Differences
Both recasting and making extra principal payments reduce your balance by the same dollar amount. The difference is what happens next. With a straight prepayment, your required monthly payment stays the same but your loan ends sooner — you save on total interest by shortening the term. With a recast, the term stays the same but your required payment shrinks, freeing up cash flow each month.
The calculator shows both paths side by side so you can compare total interest paid under each approach. If your goal is to pay less interest overall, prepayment usually wins because the balance decreases faster when the payment stays high. If your goal is lower monthly obligations — because you are changing jobs, expecting a new expense, or simply want breathing room — recasting delivers that result immediately. Some borrowers split the difference: recast to lock in a lower required payment, then voluntarily keep paying the old amount as if nothing changed, capturing the safety net and the interest savings at the same time.
Your servicer sets the minimum lump sum and the recast fee. Not all loan types are eligible for recasting — government-backed loans (FHA, VA, USDA) generally are not.