Refinancing replaces your existing mortgage with a new one — ideally at a lower rate, a shorter term, or both. It isn't free: closing costs typically run a meaningful percentage of the loan amount, so the question is never just 'is the new rate lower,' it's 'does the new rate save enough to outweigh the cost of getting it.'
The break-even calculation
Divide the total closing costs by your monthly payment savings to get the break-even point in months. If refinancing costs 4,000 and saves 150 a month, break-even is about 27 months — refinancing is worth it if you plan to stay in the home (or keep the loan) longer than that, and questionable if you might move or refinance again sooner.
Run both scenarios through our mortgage calculator: the remaining balance on your current loan at its rate and remaining term, versus the new loan amount at the new rate and term. Compare total interest from today forward, not from the original loan's start, since sunk interest already paid is gone either way.
Refinancing to a shorter term
Some homeowners refinance not to lower the payment but to shorten the term — moving from the years remaining on a 30-year loan into a fresh 15-year loan at a lower rate. The monthly payment may barely change, but total interest paid over the rest of the loan's life can drop substantially, since less time means less interest accrual and often a materially lower rate.
When refinancing doesn't make sense
If you're planning to move within the break-even window, if the rate improvement is marginal, or if you're already many years into the loan (where most of each payment is already going to principal, so restarting the amortization clock loses that progress), refinancing often costs more than it saves. Always compare the actual numbers rather than acting on a 'rates dropped' headline alone.