Mortgage Recast Calculator
After a lump sum payment, recast your mortgage to lower the monthly payment without refinancing. Keep your interest rate, just amortize less principal.
Reviewed & updated for 2026 · How we calculate
When mortgage recast beats refinancing
The 2026 mortgage landscape has created a generation of borrowers locked into 2.5-3.5% rates from 2020-2021, rates that wouldn't be available again unless the Fed dramatically cut rates. Refinancing for these borrowers means giving up a low-rate loan. Recast is the alternative: pay down principal in a lump sum, then re-amortize the remaining balance over the original term, keeping the original interest rate.
Worked example: A homeowner has a $300,000 balance, 27 years remaining at 3.25% (refinanced in 2021). Monthly P&I: $1,471. They receive a $50,000 inheritance. Refinancing at current 6.5% rates would actually raise their payment despite the lower balance. Recasting keeps the 3.25% rate; new balance $250,000 amortized over 27 years = $1,226/month. Monthly savings: $245. Total lifetime interest saved: about $79,000.
The savings come from two sources: smaller balance accruing interest, and the freed-up monthly cash flow can be invested or saved elsewhere. Recast preserves the legacy low rate while giving you the benefit of the lump sum payment. Refinance would surrender the rate advantage permanently.
Recast vs extra principal payments vs refinance
Extra principal payments reduce total interest by paying down balance faster but don't change your scheduled monthly payment. You finish the loan years sooner with the same monthly cash flow obligation. This is best if you have steady high income and want to build equity fast, but it doesn't help if you later face an income disruption.
Mortgage recast reduces your monthly payment but keeps the original payoff date. The lump sum is permanently applied; you can never get that cash back. Cash flow improves now. Total interest savings is less than aggressive extra-payment strategy, but you gain flexibility.
Cash-out refinance would actually let you tap equity rather than pay down, opposite direction. Rate-and-term refinance replaces the entire loan with new terms; it only makes sense if current rates are at least 0.75-1.0% below your current rate AND you'll stay long enough to recoup closing costs (typically 2-5 years break-even). For low-rate mortgages from 2020-2021, refinance to a higher rate is almost never worth it.
Practical considerations before you recast
- Check loan type eligibility: Conventional conforming loans (Fannie/Freddie) usually allow it. FHA, VA, USDA generally do not. Jumbo varies by lender. Ask your servicer specifically about "recast" or "re-amortization."
- Verify minimum requirements: Most lenders require a minimum lump sum ($5,000-$10,000) AND a minimum number of payments made on the loan before recast (typically 12 months). Some allow only one recast per loan; others allow multiple.
- Fee is small but check: Recast fees usually run $150-$500. On a meaningful lump sum, this is trivial, but always confirm before sending the payment.
- Opportunity cost matters: If your mortgage rate is 3%, the "savings" from paying it down is 3% (less tax benefit, if itemizing). Investing the $50,000 instead at a long-term expected 6-7% return likely outperforms. Recast is most attractive when you have unusable cash AND want lower monthly payment.
- It doesn't help if you're moving soon: Recast benefits compound over years. If you plan to sell in 1-2 years, the lump sum is better kept as down payment for the next house.
- Not all servicers allow recast: Even if your loan type technically allows it, some servicers (especially smaller ones) don't offer the option administratively. Confirm before assuming.
FAQs
What is a mortgage recast?
Recasting is paying a lump sum toward your mortgage principal, then asking the lender to re-amortize the remaining loan over the original term. This LOWERS your monthly payment without changing your interest rate. Different from refinancing (which gets a new loan) or extra principal payments (which shorten the term but keep the same payment).
How much does mortgage recast cost?
Typically $150-$500 administrative fee. Far cheaper than refinancing ($2,000-$10,000 in closing costs). Some lenders waive the fee for large lump sums. Always ask about the fee before committing.
Can any mortgage be recast?
Most conventional loans (Fannie Mae, Freddie Mac) allow recasting. FHA, VA, USDA: generally NOT recastable. Jumbo loans: depends on lender. Always confirm with your lender, recast is optional and not all lenders offer it.
Minimum lump sum for recast?
Most lenders require $5,000-$10,000 minimum payment to trigger a recast. Some require 10% or more of the loan balance. Below the minimum: the payment is applied to principal but loan term/payment don't change.
Recast vs refinance, which is better?
Recast: low cost, same rate, lower payment, same term. Best when you have a low rate you want to keep AND a lump sum. Refinance: higher cost, new rate (could be higher OR lower), choose new term. Best when rates dropped significantly OR you want to change loan type. Recast keeps a good thing going; refinance restarts.