Mortgage Recast vs Refinance vs Prepay

You just got a windfall: a bonus, an inheritance, or proceeds from selling another property. You want to throw it at your mortgage. The question is how. There are three genuinely different moves, and most articles blur them together. A recast lowers your monthly payment while keeping your rate and payoff date. A refinance swaps your loan for a new one with a different rate and term. A plain lump-sum prepayment keeps everything the same except your balance, which shortens the loan and saves the most interest. Here is the actual math for each, plus a simple rule for which one wins given your current rate.

What each option actually does

Recast (re-amortization). You send a lump sum to principal, then your lender recalculates the monthly payment over your remaining term at your existing rate. Your interest rate does not change, and your payoff date does not change. Your payment drops. Fees are small, typically a flat $150 to $500. There is usually no credit check, no appraisal, and no closing.

Refinance. You take out a brand-new loan to pay off the old one. You can change the rate, change the term, or pull out cash. But you reset the amortization clock, you re-qualify (credit, income, appraisal), and you pay closing costs that commonly run 2 to 6 percent of the loan amount. Use the mortgage refinance calculator to model a new rate and term side by side.

Lump-sum prepay (no recast). You apply the windfall to principal and keep paying your current monthly amount. Your payment never changes, but because the balance is smaller, more of each payment attacks principal, so the loan ends years early. This saves the most total interest of the three because you are effectively making extra payments for the rest of the loan.

The rule that decides it: compare your rate to today's rate

This single comparison resolves most cases:

• Your rate is at or below current market rates: never refinance. Refinancing would give you a higher rate. Choose recast if you need breathing room in your monthly budget, or prepay if cash flow is fine and you want maximum interest savings.
• Your rate is meaningfully above current market rates (often cited as roughly three-quarters of a point or more): a refinance can win because the lower rate compounds over the whole balance, not just the lump sum. Run the break-even first.

For the refinance path, the deciding number is the break-even month: closing costs divided by monthly savings. The refinance break-even calculator shows how many months you must stay in the home to come out ahead. If you might move or pay off the loan before break-even, refinancing loses even with a better rate.

One eligibility fact most posts skip: government loans usually can't recast

FHA, VA, and USDA loans are generally not eligible for recasting. Recasts are typically offered on conventional loans (those backed by Fannie Mae or Freddie Mac), and even then jumbo and some investor-held loans are excluded. If you have a government-backed loan and want a lower payment, your realistic options are refinancing (including streamline programs) or prepaying. Always confirm with your servicer, because eligibility and the minimum lump sum required to trigger a recast vary by lender, and servicing rights are often sold after closing. The Consumer Financial Protection Bureau (consumerfinance.gov) is a neutral starting point for how these loan types differ.

Worked example: a $50,000 windfall

Suppose you took a $300,000 loan at 4% over 30 years. The payment is about $1,432 per month. Five years in, your balance is roughly $271,343, and you have a $50,000 windfall. Here is how each path plays out (illustrative numbers, rounded; your figures will differ):

• Recast. Apply $50,000, re-amortize the remaining ~$221,343 over the 25 years left at 4%. New payment falls to about $1,168, a drop of roughly $264 a month. Payoff date is unchanged. Remaining interest is about $129,000.
• Prepay, no recast. Apply the same $50,000 but keep paying $1,432. The loan now pays off in about 18.2 years instead of 25, and remaining interest falls to about $90,000. That is roughly $39,000 more interest saved than the recast, because you kept the higher payment working for you.
• Refinance. Only worth modeling if a new rate is well below 4%. With closing costs of 2 to 6 percent of the balance, you would pay several thousand dollars up front, so the new rate has to recover that before break-even.

To check the new payment for any rate, term, or balance yourself, use the mortgage calculator. The trade-off is clear: recast buys you lower monthly cash flow now, prepay buys you the largest lifetime interest savings, and refinance only competes when the rate gap is large enough to overcome closing costs.

Gotchas before you commit the cash

• Recast does not lower your rate. If rates have fallen a lot, a recast leaves money on the table compared with refinancing.
• Refinancing resets the clock. A fresh 30-year term can mean more total interest even at a lower rate, because you are front-loading interest all over again.
• Prepay only helps if your loan has no prepayment penalty. Most modern conforming loans do not, but read the note.
• Tell the servicer to apply extra money to principal. Otherwise some lenders treat it as a prepaid future payment, which does nothing for interest.
• Keep an emergency fund. Money sent to a mortgage is hard to get back without a refinance or HELOC. Liquidity has value.

If you are still weighing whether refinancing makes sense at all, our explainer on what refinancing is and how it works covers the mechanics before you run the numbers.

These are estimates for planning, not financial advice. Your servicer's exact fees, minimums, and eligibility rules govern, and tax treatment of mortgage interest can change, so confirm current rules with a qualified professional or an authoritative source such as the CFPB before committing a large lump sum.

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