Mortgage Recast vs Extra Payment: Which Saves More?

A bonus lands, or an inheritance, or the check from selling your old place, and you decide some of it should go toward the mortgage. Good instinct. The trouble starts at the next step, because there are two ways to “put money toward the mortgage” and they pull in almost opposite directions: a recast and a plain extra principal payment. People mix them up constantly, and lenders rarely volunteer the difference.

So let’s settle it. Below is the distinction in plain English, the math on a realistic loan, and a way to tell which one actually fits what you’re after. If you’d rather just see your own numbers, the Decision Engine runs both at once.

The one-sentence difference

• Extra payment (prepayment): Your monthly payment stays the same, but the loan is paid off sooner, so you pay less total interest.
• Recast: Your loan is re-amortized over the same remaining term, so your monthly payment goes down, but you keep paying for the same number of years.

Put differently: an extra payment buys you time, a recast buys you cash flow.

A worked example

Say you owe $340,000 at 5.75% with 26 years (312 months) left, and you have $50,000 to put down.

Extra payment: You apply the $50,000 to principal but keep paying your original ~$2,140/month. The loan now disappears years early, and you save a large chunk of interest — often $80,000–$120,000 over the life of the loan, depending on your rate and remaining term.

Recast: You apply the same $50,000, but the lender recalculates your payment over the remaining 26 years. Your payment drops by roughly $300/month. You free up cash every month, but because you’re still paying for 26 years, you save far less total interest — typically a third or less of what prepaying saves.

The exact figures depend on your inputs, which is why a calculator beats a rule of thumb. Plug your real numbers into the Mortgage Recast Calculator and the Extra Payment Calculator to see the spread.

Why prepaying saves more interest

Interest accrues on your outstanding balance for as long as you carry the loan. When you prepay and keep your payment level, every future month has a smaller balance and you eliminate the tail end of the loan — the months that would otherwise still be charging interest. A recast lowers the balance too, but by stretching the smaller balance back over the full remaining term, you give interest more time to accumulate.

When a recast is the smarter move

Saving the most interest isn’t everyone’s goal. A recast wins when:

• Your monthly budget is tight. A lower required payment provides breathing room and reduces the risk of missing a payment.
• Your income is variable (commission, self-employment). Lower fixed obligations are safer.
• You want flexibility, not payoff. You can always choose to keep paying the old, higher amount after a recast — which then behaves like prepaying — but you’re never required to.
• You’re keeping a low rate. If your mortgage rate is well below what you could earn elsewhere, you may not want to rush to pay it off at all.

When an extra payment is the smarter move

• You want to be debt-free sooner and you can comfortably afford the current payment.
• You value guaranteed savings. Prepaying earns you a guaranteed return equal to your mortgage rate, tax-considerations aside.
• You don’t need the monthly cash flow the recast would free up.

What about investing the money instead?

There’s a third option people forget: don’t put the cash toward the mortgage at all, and invest it. If your mortgage rate is 5.75% and you could reasonably earn more than that after tax in a diversified portfolio, investing may build more wealth — though without the guarantee that prepaying offers. Our Decision Engine models this trade-off explicitly, including a breakeven return so you can see exactly how high your investments would need to perform to win.

A quick decision framework

1. Do you have an emergency fund and no high-interest debt? If not, handle those first. Money in your house is illiquid.
2. Is cash flow your problem? Recast.
3. Is being debt-free sooner your goal, and you can afford the payment? Extra payment.
4. Is your rate low and you’re comfortable with market risk? Consider investing instead.

So which one wins?

For the same lump sum, an extra principal payment saves more interest, while a recast lowers your monthly payment without shortening the loan. Neither is universally “better” — they solve different problems. Decide what you actually want (lower payment vs. faster payoff vs. maximum wealth), then run your own numbers in the Decision Engine.

Numbers here are estimates; confirm them with your lender before moving money. None of this is personal financial advice.

Run the numbers in our calculator →

Frequently asked questions

Does a recast save more than an extra payment?

No. With the same lump sum, prepaying (extra payment) almost always saves more total interest because it shortens the term. A recast keeps the term and lowers the payment, so you pay interest for the same number of years.

Why would anyone recast instead of prepaying?

Cash flow. A recast lowers your required monthly payment, which helps if your budget is tight or your income is variable. Prepaying keeps the higher payment but gets you out of debt sooner.

Can I do both?

Sometimes. You can prepay principal whenever you like, and separately request a recast to reset the required payment lower. Each lender has its own rules and a recast fee (typically $150–$500).