How to Use This Calculator
This mortgage recast calculator helps you understand what happens when you make a large lump-sum payment toward your principal and ask your lender to recalculate your monthly payment. Here's what each field means:
- Current Loan Amount: The total amount you still owe right now
- Interest Rate: Your current mortgage interest rate (stays the same after recast)
- Years Remaining: How many years are left on your loan
- Lump Sum Payment: The large amount you're planning to pay toward principal
- Lender Fee: What your lender charges for the recast (typically $250-500)
What Is a Mortgage Recast?
A recast is one of those financial moves that sounds complicated but is actually pretty straightforward. Here's the basic idea: you take a chunk of money—let's say from a bonus, inheritance, or savings—and you throw it at your mortgage principal. Then you ask your lender to do the math again and recalculate your monthly payment based on the smaller amount you now owe.
Think of it like this: imagine you borrowed $300,000 for your house at 4% interest with 25 years to pay back. Your current monthly payment is about $1,432. Now let's say you have $50,000 you want to use strategically. You give it to your lender, they subtract it from what you owe (leaving $250,000), and they recalculate your payment based on that smaller balance. Your new payment drops to about $1,100 a month—that's roughly $332 in monthly savings forever.
The beautiful part? Your interest rate doesn't change. Your term doesn't change. All you're doing is shrinking the amount you borrowed, which automatically lowers what you pay each month.
Why Choose a Recast Over Refinancing?
Let's be honest—refinancing sounds like it might do the same thing, but it's way more expensive. A recast costs $250-500. Refinancing typically costs $5,000-15,000 because they're essentially giving you a brand new loan. They'll do a credit check, order an appraisal, and handle a bunch of paperwork.
With a recast, there's no credit check. No appraisal. You just call your lender and say, "Here's money. Rewrite my payment." It's simple and cheap.
When a recast beats refinancing:
- You want to lower your payment but don't want to change your rate
- You want to avoid closing costs
- You don't want a hard credit inquiry
- You're planning to stay in your house
When refinancing wins:
- Interest rates have dropped significantly (1%+ difference)
- You want a shorter loan term
- You want to do a cash-out refinance
- You need a new appraisal (maybe your home appreciated)
Real Numbers Example
Let's walk through an actual scenario so this feels real:
You have a $300,000 mortgage at 4% interest with 25 years remaining. Your current monthly payment is $1,432, and you have $50,000 sitting in savings that you want to use wisely.
You decide to recast. After paying the lender's $500 fee, you put $49,500 toward principal. Your new loan balance is $250,500. Your lender recalculates everything at that same 4% rate over the same 25 years.
Your new monthly payment? About $1,100.
That's $332 less every month. Over the next 25 years, that's nearly $100,000 in savings. And you only spent $500 to make it happen.
Important Details About Recasts
Most lenders won't let you recast with a tiny payment. They usually require a minimum lump sum of $10,000-$20,000 (sometimes higher). This is partly because the fee wouldn't be worth it on a smaller payment.
Also, recasts only work with loans that are in the repayment phase. If you have a construction loan or a loan during interest-only period, recast might not be available.
Some lenders are more recast-friendly than others. Fannie Mae and Freddie Mac loans are typically easy to recast. If you have an FHA loan or a portfolio loan, ask your servicer—the rules vary.
Strategic Tips
Timing Matters: If you're planning to sell your house in a few years, a recast doesn't help much because you're about to stop paying that mortgage anyway. Refinancing that lowers your rate might be better if you're keeping the house.
Stack Your Windfalls: You don't have to use all your windfalls at once. Some people do multiple recasts over years as they get bonuses or tax refunds.
Compare to Extra Payments: You could also just make extra payments without recasting. But a recast officially lowers your payment, which helps your monthly cash flow. Extra payments without a recast just shorten your loan term—your payment stays the same.
References
- Fannie Mae Mortgage Recast Guidelines
- Federal Reserve Bank - Home Mortgage Disclosure Data
- National Mortgage Bankers Association
- Consumer Financial Protection Bureau - Understanding Loan Options
This calculator is for educational purposes to help you understand the basic math of mortgage recasts. Every mortgage situation is unique—rates, terms, and lender policies vary. Talk to your actual lender about whether a recast is available for your loan and what they'd charge. Don't make financial decisions based solely on this calculator.