By Meraj Uddin Provat · Last reviewed May 23, 2026 · Editorial Standards
A mortgage recast is the quiet alternative to refinancing: pay a lump sum toward principal, the lender re-amortizes the same loan, and your payment drops — same rate, same payoff date, no closing costs, no credit check. It’s rarely advertised because lenders make little from it. This calculator shows exactly what it does to your payment.
Mortgage Recast Calculator
Put a lump sum toward principal, keep the same rate and term, get a lower payment. See exactly how much lower. Updates as you type.
A recast re-amortizes your loan over the same remaining term at the same rate after a principal lump sum, lowering the payment without refinancing. Not all loans are eligible (most government loans aren’t). Keeping the old payment after the lump sum (or just paying extra principal) saves more total interest but doesn’t lower the required payment. Estimates only — not a loan offer or financial advice.
How to use this calculator
Enter your current balance, rate, and months remaining, then the lump sum you'd apply and the lender's recast fee. You'll see your new (lower) payment, how much it drops, and an honest comparison against simply keeping your old payment instead.
What a recast actually does
A recast keeps three things fixed: your interest rate, your remaining term, and the type of loan. It changes one thing: it spreads a now-smaller balance across the same remaining months, so each payment is lower. You are not refinancing — there's no new loan, no closing costs, no rate change, usually just a small administrative fee. It's most useful when you've come into a lump sum (sale proceeds, bonus, inheritance) and want lower required payments without touching a low rate you'd lose in a refinance.
Recast vs refinance
Refinancing replaces the loan — new rate, new term, full closing costs. If your current rate is low, refinancing into today's market reprices your whole balance upward, which a recast never does. A recast can't lower your rate, but it can't raise it either. When the goal is "lower my payment and I have cash," and the rate isn't the problem, a recast is the cheaper, lower-risk tool.
The honest trade-off (most calculators hide this)
A recast lowers your required payment — but it also re-stretches the lump sum over the full remaining term, so it does not maximize interest saved. If your cash flow is fine, the cheaper move is often to apply the same lump sum and keep paying the old payment (or just pay extra principal): the loan then pays off years early and saves more total interest. This calculator shows both, because the right choice depends on whether you need lower payments or lower total cost:
- Need breathing room in the monthly budget → recast wins (guaranteed lower payment)
- Cash flow is comfortable, want lowest total cost → lump sum + keep old payment wins
When you can't recast
Many loans aren't eligible — most government-backed loans (FHA, VA, USDA) generally can't be recast, and some lenders or servicers don't offer it at all. There's usually a minimum lump sum required. Always confirm eligibility, the exact fee, and the minimum with your servicer before counting on it.
Frequently asked questions
Does a recast lower my interest rate? No. The rate and remaining term stay exactly the same. Only the balance and therefore the payment change. To change the rate you'd need to refinance.
Recast or refinance — which is better? If your rate is already low and you just want a lower payment from a lump sum, recast (cheaper, no closing costs, keeps your rate). If you can meaningfully lower your rate, compare a refinance — but check the break-even.
Does recasting save me money? It saves some interest by lowering the balance, but less than if you applied the same lump sum and kept your old payment. Recast optimizes for a lower monthly payment, not lowest total interest.
What does a recast cost? Usually a small flat fee, often around $150–$500, versus thousands in closing costs for a refinance. There's typically a minimum lump-sum requirement too.
Can I recast an FHA or VA loan? Generally no. Government-backed loans usually aren't eligible. Confirm with your servicer, since policies vary.
Methodology
The current payment is the standard amortization of your balance at the given rate over the remaining months. The new payment re-amortizes the balance minus the lump sum over the same rate and remaining months. Interest saved compares total payments on each path. The "keep old payment" comparison simulates paying the original payment on the reduced balance until payoff. Eligibility, fees, and minimums vary by lender. Estimates only — not a loan offer or financial advice.
Written by the CalcCottage team. We show the real number, not the marketing number.