Compare the break-even month to how long you'll stay in the home. If you plan to move before break-even, you'll lose money even at a lower rate.

Rolling closing costs into the principal raises the new balance, which slightly increases monthly payment and the total interest paid. The calculator lets you toggle this to see both scenarios.

There's no fixed number — 1% used to be the rule, but with smaller balances or shorter remaining terms even 0.5% can break even quickly. Always compute it, don't rely on a rule of thumb.

Yes — a standard refi starts the amortization clock over. You can offset this by choosing a shorter new term (e.g., refinance into a 15-year instead of another 30-year).

Points are pre-paid interest. They make sense only if you keep the loan long enough that the monthly savings recover the upfront cost — exactly the same break-even math as the refi itself.