Refinance Calculator

How this refinance calculator works

Enter your remaining loan balance, your current rate and remaining term, then the new rate and term you're offered, plus the closing costs to refinance. The calculator runs the same amortization math used across BriskToolbox to find your current payment and your new payment, then reports the numbers that actually matter for the decision: how much you save each month, how many months it takes for that saving to repay the closing costs (break-even), how much interest you save (or lose) over the life of the loan, and the net result once closing costs are subtracted.

Break-even, explained

Refinancing isn't free — you pay closing costs to get the new loan. Break-even is simply closing costs ÷ monthly savings: the number of months of lower payments it takes to recover what you spent. If your monthly savings is $292.54 and closing costs are $6,000, break-even is 6,000 ÷ 292.54 ≈ 20.5 months, which this calculator rounds up to 21 months — the first full month you're ahead. If you plan to stay in the home (or keep the loan) longer than the break-even period, the refinance is generally worth it on cost grounds; if you might sell or refinance again sooner, the closing costs may never fully pay for themselves.

A worked example

Say you have a $300,000 balance on a 30-year mortgage at 7.0%, with the full 30 years (360 months) remaining, and you're offered a refinance at 5.5% for the same 360-month term, with $6,000 in closing costs. Your current payment is $1,995.91/month; the new payment is $1,703.37/month — a saving of $292.54 every month. Break-even on the $6,000 in costs lands at 21 months, well under two years. Run the full remaining schedule and the interest still owed under the old loan is about $418,527, versus about $313,212 under the new one — a lifetime interest saving of roughly $105,315, or $99,315 once the $6,000 in closing costs is subtracted. That net figure, not the monthly payment, is the real answer to "is this refinance worth it."

When refinancing does — and doesn't — make sense

Refinancing tends to make the most sense when the new rate is meaningfully lower than your current one, you plan to keep the loan past the break-even point, and you keep the new term at or below your remaining term so you're not restarting the amortization clock. It tends to make less sense when the rate improvement is small, you expect to move or pay off the loan soon, or the only way the payment drops is by stretching the term back out — which is where the numbers can quietly work against you even though the headline payment looks better.

The longer-term trap

Here's the case worth watching closely. Say you're 10 years into a $300,000 loan at 7% (120 months, $3,483.25 remaining monthly payment) and you refinance into a brand-new 30-year loan at a lower 6.5% rate, paying $3,000 in closing costs. Your payment drops enormously — $1,896.20/month, a saving of $1,587.05 — and break-even arrives almost immediately, in about 2 months. It looks like an easy win. But because the new loan resets the clock to a full 30 years, the interest still owed under the old 10-year payoff was only about $117,991, while the new 30-year loan will cost about $382,633 in interest — a lifetime interest increase of roughly $264,643, and a net loss of about $267,643 once closing costs are included. The lower payment was real, but it came from spreading the same balance over 20 extra years, not from the rate improvement alone.

What counts as closing costs

Closing costs typically include the lender's origination and application fees, an appraisal, title search and title insurance, recording fees, and any discount points you choose to pay to buy the rate down further. Your Loan Estimate will itemize all of these — add them up for the "closing costs" figure above. Rolling closing costs into the new loan balance instead of paying them upfront changes the math slightly (you'd finance a bit more than your current balance); this calculator assumes you're comparing against your exact current balance, so add rolled-in costs to the balance if that's your plan.