Guide to Mortgage Refinancing

What a refinance is

To refinance is to replace your current mortgage with a new one — usually to get a lower interest rate, sometimes to change the term or pull out cash. The old loan gets paid off in full by the new loan, and you start over with fresh paperwork, a fresh rate, and a fresh set of closing costs.

That last part is the catch. A refinance is not a rate adjustment — it’s a whole new loan, with its own fees. Lower payments are real, but you pay upfront to get them. The only question that matters is whether the savings outrun the cost before you sell, move, or refinance again.

The one test: break-even months

Skip the rules of thumb. There is exactly one calculation that decides a rate-and-term refinance:

Break-even months = closing costs ÷ monthly payment savings.

That’s how long the lower payment takes to earn back what you paid to close. Past that month, the savings are yours to keep. Before it, you’re still in the hole.

The figure starts on a common case: dropping a $300,000 loan a full point, from 6.75% to 5.75%, trims the payment about $195 a month. At $5,000 to close, that’s $5,000 ÷ $195 ≈ 26 months before you’re ahead — just over two years. Drag the rate cut to watch a smaller cut push that break-even later.

The catch the savings hide

The break-even test answers “is the rate cut worth the fee?” It does not answer “will I pay less interest overall?” — and those are different questions.

When you refinance into a new 30-year loan, the clock resets. Your old loan might have had 24 years left; the new one stretches the balance back across 30. Early payments on any mortgage are mostly interest and barely touch the balance: on the $300,000 example above (at 6.75%), the first month’s payment is roughly $1,690 in interest and barely $260 toward the balance. That front-loaded split is how amortization works. So a reset quietly re-loads years of interest you’d already worked past — a lower rate can still mean more total interest if you also restart the term.

Two ways to keep the rate cut without the reset:

• Keep paying your old payment. Before you close, write down your current required payment, since the new paperwork will only show the lower figure. Then take the new, lower required payment but send the bank the old, higher amount, and tell your servicer — the company that collects your payments, named on your closing paperwork and often not the lender you applied with — to apply the extra to principal; otherwise many hold it as a prepaid payment instead of shrinking the balance. Look for an “apply to principal” option in the payment portal, or call to confirm. You finish close to your original payoff date, now at a lower rate.
• Refinance to a shorter term. Rolling a 30-year into a 20- or 15-year locks in the shorter horizon — and a 15-year almost always carries a lower rate than a 30-year (the lender’s money is exposed for less time, and they price that lower risk in), so the rate saving and the shorter schedule reinforce each other. The payment may not drop much, but the total interest falls sharply.

The “1% rule” is a shortcut, not the answer

You’ll hear that refinancing is worth it once you can cut your rate by a full percentage point. It’s a rough flag, not a decision. A smaller cut on a large balance with cheap closing costs can break even in a year; a bigger cut on a small balance with steep fees might take five. The break-even math doesn’t care about the size of the rate cut — only about the dollars saved per month against the dollars paid to close.

Rate-and-term vs. cash-out

Most of this guide is about a rate-and-term refinance: same balance, better terms. A cash-out refinance is a different animal: you borrow more than you owe and take the difference in cash, using your home as collateral — the asset the lender can take if you stop paying. That word collateral is the catch: a rate-and-term refi risks nothing new, but a cash-out puts the house itself on the line. It can make sense when the money goes back into the home, like a roof that has to be replaced or an addition that adds lasting value, not into spending that leaves no asset behind. But turning unsecured debt (credit-card balances, backed by no asset) or everyday spending into a 30-year loan against the roof over your head deserves caution.

When it’s clearly worth it — and when it isn’t

Lean yes when the rate cut is real, closing costs are modest, and you’re confident you’ll hold the loan well past the break-even month — and especially if you keep paying the old payment or shorten the term.

Lean no when you might move or refinance again before break-even, when the “no-closing-cost” offer just buries the fees in a higher rate, or when the only way the new payment looks better is by restarting a 30-year clock you were years into. The no-closing-cost trap is the sneaky one: instead of charging you at the table, the lender quotes a rate a fraction of a point higher than you’d otherwise get and earns those costs back from the larger interest stream. That higher rate is permanent, so the longer you hold the loan, the worse it looks.