Mortgage Recast Calculator
A mortgage recast re-amortizes your loan after a lump-sum principal payment: same interest rate, same payoff date, lower monthly payment. Enter your remaining balance, rate, remaining term and the lump sum to see your new payment and how much interest you save.
Enter your values
Result
Principal & interest only — taxes and insurance stay the same. Your payoff date does not change with a recast.
How to use the Mortgage Recast Calculator
- 1Enter remaining loan balance in the form on the left.
- 2Fill in the remaining fields — the result updates automatically as you type.
- 3Review the highlighted result and the supporting breakdown on the right.
- 4Use Copy, Share or Print to save or send your result.
What is a mortgage recast?
A recast (re-amortization) happens when you make a large one-time principal payment and your lender recalculates the monthly payment on the new, smaller balance — keeping the original interest rate and the original payoff date. Because the balance dropped but the term didn't, every payment from then on is lower.
Recasting differs from refinancing in two important ways: there is no new loan, so no closing costs, credit check or rate change — just a small administrative fee, typically $150 to $500. And it differs from simple extra payments, which shorten the loan but leave the required monthly payment unchanged.
Recast vs. refinance vs. extra payments
Choose a recast when you like your current rate and want lower required payments — common after selling a previous home, receiving a bonus or an inheritance. Choose a refinance when today's rates are meaningfully below yours; the closing costs only pay off if the rate drop is large enough. Make plain extra payments when your goal is to be debt-free sooner rather than to lower the monthly bill.
Not every loan can be recast: conventional loans usually qualify, while FHA, VA and USDA loans generally do not, and most lenders require a minimum lump sum of $5,000–$10,000. Call your servicer before planning around one.
How the numbers are calculated
The calculator uses the standard amortization formula twice — once on your current balance and once on the balance after the lump sum — over the same remaining term and rate. The difference between the two payments is your monthly saving, and that saving accumulated over the remaining months, minus the lump sum itself, is the interest you avoid paying.
Frequently Asked Questions
▸Does a recast change my interest rate or payoff date?
No. The rate and the final payment date stay exactly the same — only the monthly payment drops, because the same term now amortizes a smaller balance.
▸How much does a mortgage recast cost?
Most servicers charge a flat fee between $150 and $500. There are no closing costs, appraisal or credit check, which is why recasting is far cheaper than refinancing.
▸Which loans can be recast?
Most conventional (Fannie Mae / Freddie Mac) loans qualify. FHA, VA and USDA loans typically cannot be recast — for those, refinancing or extra principal payments are the alternatives.
▸Is it better to recast or pay extra every month?
They serve different goals. A recast lowers your required payment and improves monthly cash flow; extra payments keep the payment the same but pay the loan off earlier and save more total interest.