Mortgage Recast Calculator – Calculate New Monthly Payment After Lump Sum
See your new payment after a lump sum and compare recasting with keeping your current payment. Enter your loan from the original details or from your latest statement.
Loan Details
Your Recast Results
Interest saved after fee: —Recast vs. Keep Paying vs. Do Nothing
| No lump sumdo nothing | Lump sum + recastlower payment | Lump sum, keep old paymentfaster payoff |
|---|
Remaining interest by option
Amortization Schedule
Principal and interest only. Month 1 is the first payment after your lump sum. Dates assume that payment is next month.
Last updated:
Recast Mortgage Calculator: Lower Your Loan Payments Easily
Use this calculator to see your new monthly payment after you pay a lump sum toward principal and your lender re-amortizes the loan. It also shows what happens if you make the same payment but keep paying your current amount, so you can pick the option that fits your goal: a lower bill or a faster payoff.
What Is a Mortgage Recast?
A mortgage recast, also called re-amortization, is when you pay a large lump sum toward principal and your servicer recalculates your monthly payment on the lower balance. Your interest rate stays the same, and so does your payoff date. Only the principal-and-interest part of the payment changes.
Recasts are mainly offered on conventional loans. FHA, VA and USDA loans generally can't be recast. Fannie Mae's servicing rules, for example, let a servicer lower only the principal-and-interest payment after a substantial principal payment, using the current rate and the remaining term.
How to Use This Calculator
If you know your original loan amount, term and how many payments you've made, use From original loan and the calculator works out your current balance. If it's easier, switch to From my statement and copy the unpaid principal balance and remaining term from your latest statement. You can also enter the principal-and-interest payment shown there, which matters if you've been paying more than required.
Then add your rate, the lump sum, and your servicer's recast fee. The results compare doing nothing, recasting, and keeping your current payment after the lump sum. "Fee break-even" is the number of months until the interest you save is larger than the fee.
Escrow is optional. Property taxes and homeowners insurance don't change when you recast, so the calculator simply adds the amount you enter to each payment. If you pay PMI, a large enough lump sum may let you ask to cancel it, which the calculator doesn't include; see the PMI removal calculator for that.
Example
A $200,000 loan at 5% for 30 years has a principal-and-interest payment of about $1,074. After 10 years the balance is about $162,684, with about $94,990 of interest still to come. Suppose you pay $50,000 toward principal.
If you recast, the payment drops to about $744 a month for the remaining 20 years, and remaining interest falls to about $65,796. That saves roughly $29,200 and frees up about $330 a month.
If you keep paying $1,074, the loan is paid off in about 11 years and 7 months instead of 20 years, and remaining interest falls to about $35,795. That saves roughly $59,200, about twice as much, but your required payment doesn't change.
What Different Lump Sums Do
For a $350,000 balance at 6.25% with 26 years left (current payment about $2,272):
| Lump sum | New payment after recast | Monthly savings | Interest saved – recast | Interest saved – keep old payment | Paid off sooner – keep old payment |
|---|---|---|---|---|---|
| $10,000 | $2,207 | $65 | $10,255 | $37,972 | 1 yr 9 mo |
| $25,000 | $2,110 | $162 | $25,638 | $86,310 | 4 yrs |
| $50,000 | $1,948 | $325 | $51,277 | $149,963 | 7 yrs 4 mo |
| $100,000 | $1,623 | $649 | $102,554 | $236,677 | 12 yrs 4 mo |
A useful shortcut: the principal-and-interest payment falls by the same percentage as the share of the balance you pay off. Paying down 10% of the balance cuts that part of the payment by 10%.
Recast vs. Keep Paying vs. Refinance
| Recast | Lump sum, keep old payment | Refinance | |
|---|---|---|---|
| Interest rate | Unchanged | Unchanged | New rate |
| Monthly payment | Lower | Unchanged | Depends on new rate and term |
| Payoff date | Unchanged | Earlier | Resets |
| Interest saved | Some | Most | Depends on the rate drop |
| Credit check | No | No | Yes |
| Typical cost | $150–$500 fee | None | Closing costs |
Recast Requirements
The rules come from whoever owns your loan and from your servicer, so they vary. Expect to need a conventional loan that is current, a minimum principal payment (commonly $5,000 to $10,000) and a one-time fee (commonly $150 to $500). Some servicers also make you wait after closing, limit you to one recast a year, or exclude interest-only and option ARM loans.
Here is what three large servicers published in their own recast documents when we last checked (October 2026):
| Servicer | Minimum principal payment | Fee | Other published rules |
|---|---|---|---|
| Mr. Cooper | $10,000 | Up to $250 | No credit check; Ginnie Mae, interest-only, and option ARM loans not eligible |
| NewRez | $5,000 | $250 | Fannie Mae or Freddie Mac loans; not within 60 days of closing; once a year |
| RoundPoint | $10,000 | $300 | Conventional loans only; signed recast agreement required |
These rules change. Confirm the current requirements with your own servicer before you send any money.
How to Request a Mortgage Recast
- Call your servicer (the company named on your statement) and ask whether your loan can be recast.
- Get the rules in writing: the minimum payment, the fee, any waiting period and how long it takes.
- Submit the request and pay the fee the way your servicer asks.
- Send the lump sum marked "principal only." Some servicers want it before the request and some after approval.
- Sign the recast agreement if there is one, then check that your next statement shows the lower payment.
Is Recasting Right for You?
A recast makes the most sense when you have a lump sum, such as a bonus, an inheritance or the proceeds from selling a previous home, and you want a lower required payment without giving up your current rate. It's especially useful when today's rates are higher than yours, since refinancing would mean a higher rate. There's no new loan application, so your credit score doesn't matter.
It's a weaker choice if your rate is well above today's rates (a recast never lowers the rate), if your main goal is to be debt-free sooner (keeping your old payment saves more), or if the lump sum would drain your emergency fund. Money put into home equity is hard to get back without borrowing against the house, and paying off higher-interest debt such as credit cards usually saves more first.
To compare today's rates, check Freddie Mac's weekly mortgage rate survey. To test ongoing extra payments instead of a one-time lump sum, use the mortgage payoff calculator.
Methodology & Sources
Payments use the standard fixed-rate amortization formula, calculated monthly and rounded for display. The recast scenario re-amortizes the reduced balance at the same rate over the same remaining term; the keep-paying scenario applies your existing payment until the balance reaches zero. Results cover principal and interest, plus escrow only if entered.
This calculator provides estimates for informational purposes only and is not financial advice. Your servicer's figures may differ.