Mortgage Recast Calculator
Your new payment after a lump sum, and whether recasting or prepaying saves you more
Last updated: October 2026
Your Loan and Lump Sum
Set by your servicer. Ask for the fee and any minimum lump sum.
Often eligible for a recast
Conventional loans are the type most often recast. Your servicer decides, and many set a minimum lump sum and require that your payments are current. Always confirm with your servicer.
Recast or prepay and keep your payment?
| No lump sum | Recast | Prepay, same payment | |
|---|---|---|---|
| Monthly payment | $1,880.48 | $1,544.68 | $1,880.48 |
| Payments left | 324 | 324 | 208 |
| Interest still to pay | $329,276 | $270,477 | $160,469 |
| Fee | $0 | $250 | $0 |
| Interest saved, after fees | $0 | $58,549 | $168,807 |
Prepaying saves $110,258 more and ends the loan 9 years 8 months early. Recasting frees up $335.80 a month instead.
How a mortgage recast works
You send your servicer a lump sum, it is applied to principal, and the servicer works out a new level payment that pays off the lower balance over the time you have left. The math is the standard payment formula run again on the new balance with the same rate and the same number of remaining months. Because the payment is proportional to the balance, a lump sum that cuts the balance by 18% cuts the payment by 18% too.
The alternative is to make the same lump-sum payment and not ask for a recast. Your required payment stays the same, so more of each payment goes to principal and the loan ends early. That saves more interest, but it does not help your monthly budget until the loan is gone.
Worked example
You owe $280,000 at 6.75% with 27 years left, so your payment is $1,880.48. You put $50,000 toward principal and pay a $250 recast fee. The new balance of $230,000 over the same 27 years gives a payment of $1,544.68, $335.80 less each month. You pay $58,799 less interest over the rest of the loan, or $58,549 after the fee.
If you make the same $50,000 payment and keep paying $1,880.48, the loan ends 9 years 8 months early and you save $168,807 in interest, with no fee.
Who can recast
- Conventional loans owned by Fannie Mae or Freddie Mac are the type most often recast. The servicer decides and sets the fee and minimum lump sum.
- FHA, VA and USDA loans are generally not eligible. A principal prepayment still works on these loans.
- Jumbo and portfolio loans follow the lender's own policy.
- You usually need to be current on payments, and some servicers only recast after the loan has been open for a set period.
Related tools
If market rates have fallen, compare a refinance with the refinance vs recast calculator. To see what steady extra payments do instead of a lump sum, use the mortgage payoff calculator, and see the month-by-month detail in the amortization schedule calculator. Start from the mortgage calculator for the full monthly cost with taxes and insurance, or read paying off your mortgage early vs investing before you send a large sum.
Frequently Asked Questions
What is a mortgage recast?
A recast, also called re-amortization, is when you pay a lump sum toward principal and your servicer recalculates your monthly payment on the lower balance. Your interest rate and payoff date stay the same; only the payment goes down. There is no new loan, no credit check and no appraisal, which is why it costs far less than a refinance.
How much does a mortgage recast cost?
Servicers set their own fee, usually a flat amount of a few hundred dollars, and many also require a minimum lump sum. Ask your servicer for both before you send the money. Enter the fee above and the calculator shows the interest saved after it and how many months of lower payments it takes to earn the fee back.
Can I recast an FHA, VA or USDA loan?
Generally no. Government-backed loans are usually not eligible for recasting. You can still make a lump-sum principal payment on them: it cuts interest and shortens the loan, but your required payment stays the same. Conventional loans are the type most often recast, and the final decision is your servicer's.
Is it better to recast or just prepay?
Prepaying and keeping your old payment saves more interest, because you keep paying the loan down faster. Recasting gives you a lower required payment and more room in your monthly budget. In the example on this page, a $50,000 lump sum on a $280,000 loan at 6.75% saves $58,799 if you recast and $168,807 if you keep paying the old amount.
Does recasting change my interest rate?
No. A recast keeps your rate and remaining term. If market rates are well below your rate, compare a refinance, which can lower the rate but comes with closing costs. The refinance vs recast calculator compares the two.
When does a recast make sense?
Recasting is common after selling a previous home once you have already bought the next one, after an inheritance or bonus, or whenever you want a lower required payment without giving up a good rate. If you would rather be debt-free sooner, prepaying without a recast does more.