Mortgage Recast Calculator
See how a lump-sum payment toward your principal could lower your monthly payment without refinancing. Figures below cover principal and interest only.
What Is a Mortgage Recast?
A mortgage recast — sometimes called re-amortization — is when your loan servicer recalculates your monthly principal-and-interest payment after you make a lump-sum payment toward the principal balance. The recast lowers your balance first, then spreads the smaller balance across your existing loan term, which is why the new payment comes out lower.
How a Mortgage Recast Changes Your Payment
A recast reduces your principal balance by the amount of your lump-sum payment. Your interest rate typically does not change, and your remaining loan term typically does not change either — the servicer simply re-runs the amortization math on the smaller balance over the months you have left. Because the rate and term stay the same, the new principal-and-interest payment is calculated directly from the reduced balance, which is the calculation this tool performs above.
Mortgage Recast vs. Refinancing
Refinancing replaces your loan entirely — new rate, often a new term, new closing costs, and a new credit and income review. A recast keeps your existing loan, rate, and term in place and only adjusts the balance and payment. That generally makes a recast simpler and cheaper than a refinance when your goal is a lower payment rather than a lower rate, but not every loan or servicer offers it.
When a Recast May Be Worth Considering
A recast can be worth a look after a windfall — an inheritance, a bonus, proceeds from selling another property — that you'd rather put toward a lower monthly payment than toward a full refinance. It can also make sense if your rate is already competitive and refinancing wouldn't improve it enough to justify new closing costs.
Important Questions to Ask Your Lender
Eligibility, minimum lump-sum requirements, and any recast fees are set by your specific lender and loan agreement — they vary and this tool does not assume any particular figure on your behalf. Before planning around a recast, ask your servicer:
- Does my loan program allow a recast, and is there a minimum lump-sum amount?
- What is the recast fee, and how is it collected?
- How long does processing typically take once the lump sum is received?
- Will the new payment amount be confirmed in writing before it takes effect?
This calculator provides estimates for educational purposes only and does not constitute financial, lending, tax, or legal advice. Actual recast eligibility, fees, payment amounts, and terms must be confirmed with your mortgage servicer.